Groups under uncertainty: An examination of confidence in group decision making

ORGANIZATIONAL

BEHAVIOR

AND HUMAN

DECISION

PROCESSES

Groups under Uncertainty: An Examination Group Decision Making JANET University

of Illinois

52, 126155 (1992)

of Confidence

in

A. SNIEZEK at Urbana-Champaign

This paper examines confidence in decisions that are made by groups under uncertainty. A variety of theoretical perspectives-information processing, motivational, social, and organizational-are used to derive predictions about group confidence and discuss its implications. Confidence assessment data from decision-making groups in various studies by Sniezek and colleagues and others are reviewed. It is argued that theory and research on group decision making can benefit from consideration of a group’s confidence in its decision as well as the objective quality of that decision. o wz Academic press, I~IC.

Beliefs about the goodness of one’s judgments or choices can be expressed by ratings or subjective probabilities about the likelihood of events. Such beliefs, termed confidence in judgment or choice, will determine if and how those judgments or choices are used by the decision makers themselves-and maybe even by others. Put another way, confidence is postulated to mediate the behaviors of selecting a course of action and following that course. It follows that inappropriate confidence is a threat to successful decision making and implementation. Disaster often results from poor decisions made with great confidence. Conversely, the potential benefits of an accurate judgment may be lost if its accuracy is in doubt. Because of this, it has been argued that confidence in judgments and choices may be just as important to the ultimate outcomes of the decision as the quality of the decision itself (Sniezek & Henry, 1989). Empirical observation of confidence in individual judgment and choice has increased substantially in the years since the review by Lichtenstein, Fischhoff, and Phillips (1982) in both quantity and breadth. Recent researchers have examined such issues as cross-national differences (Bontempo, 1990; Yates et al., 1989) and overconfidence in knowledge related Comments that led to the enhancement of the quality of this paper-as well as the author’s confidence in it-were provided by James H. Davis, Editor of this Special Issue, J. Keith Mumighan, Susan Straus, and members of my graduate seminar on decision making at the University of Illinois. Their generous assistance is greatly appreciated. Address correspondence and reprint requests to Dr. Janet A. Sniezek, Department of Psychology, University of Illinois, 603 E. Daniel, Champaign, IL 61820. 124 0749-5978192$5.00 Copyright 0 1992 by Academic Press, Inc. All rights of reproduction in any form reserved.

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to voting behavior (Paese & Feuhr, 1991). Yet there has been comparatively little work on confidence for decisions made by individuals in social contexts or by groups. It is clear from decades of research on group judgment and choice that-as for many areas of inquiry-theory and data for individuals do not necessarily apply to groups (see Einhom, Hogarth, & Klempner, 1978; McGrath, 1984; Sniezek & Henry, 1989; Stasser dz Davis, 1981). The process of judging or choosing in a group involves phenomena, such as disagreement, that do not exist for individuals. And, the final judgments or choices of groups can differ substantially from those that are made by comparable or the same persons working independently. The degree to which theory and data on individual confidence in judgment and choice apply to groups has not been investigated until relatively recently. The major purpose of this paper is to answer: How confident are groups about their judgments and choices? The first task of the paper is a brief clarification of this purpose by answering some preliminary questions: Which groups and what kinds of judgments and choices? What is meant by confidence? And, “How confident . . . ” compared to what? Immediately below is a discussion of (a) the groups and task that are considered, (b) the meaning of group confidence, and (c) the standards to which group confidence can be meaningfully compared. Subsequently, the paper turns to an examination of the notion of group confidence as an important output of the group decision-making process. Group confidence is discussed with respect to models of group effectiveness from the literature on group performance. The remainder of the paper is devoted to theory and data on confidence in decision-making groups. Group

and Task Characteristics

This paper will address decision-making tasks by groups with two features. First, the members of the group share the objective of maximizing the quality of their decision with respect to some identifiable criterion. Though groups will often have conflicts between members’ collective and individual interests (Sniezek & May, 1990; Sniezek, May, & Sawyer, 1990), the collective interest in maximizing decision quality can dominate. This objective will be assumed to dominate for decision-making groups here; thus, incentives for other individual outcomes (e.g., gaining power) will not be discussed. The second feature of situations of interest is that the groups operate under uncertainty about which alternative is superior throughout the task. As Hart (1985) pointed out, groups are typically assigned to tasks for which it is difficult to know when a good decision has been reached. Hence the group’s own evaluation of its product is often an

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important-and sometimes the only-ingredient in the determination of group effectiveness. Decision-making tasks for which no alternative can ever be deemed superior, or for which one alternative is demonstratively correct by the group during interaction (e.g., “eureka” problems), are not of interest in this paper. The relevant situations are those in which group members are motivated to maximize decision quality, but have some degree of uncertainty about the relative quality of alternatives throughout the task. Defining

Group Confidence

Many papers-including this one-use both the “uncertainty” and “confidence” terms to refer to the same construct. That is, confidence in one’s choice is the converse of subjective uncertainty in one’s choice. However, methods for assessing confidence necessarily vary with features of the decision-making task. These methods are worth examining since variations in confidence assessment will reduce our ability to generalize over studies and draw conclusions about group confidence. Confidence is frequently measured by obtaining ratings on a predeflned scale. In behavioral decision research, a rating of confidence is interpreted as an indicator of the strength of belief in the quality of one’s judgment or choice. Rating scales have the advantage of being easily understood by decision makers; but they are limited in that it is rare (and nontrivial) to establish that ratings have interval scale properties. Further, rating statistics can be interpreted within the context of a particular study, but comparison across studies are more problematic. How, for example, does 4.5 on a 7-point scale with anchors 1 = “extremely doubtful” and 7 = “extremely confident” compare to 4.5 on a 7-point scale with anchors 1 = “no confidence” and 7 = “very high confidence”? Alternative procedures for confidence assessment are based on the representation of a decision maker’s beliefs in terms of a subjective probability distribution over alternatives. Assessment methods using subjective probabilities have one major advantage over ratings: It is possible to evaluate the appropriateness of confidence levels if one has knowledge of outcomes. This will be explained further below. For choice tasks, the decision maker can be asked to report the subjective likelihood that a given alternative is best according to some specified criterion. A confidence assessment in a choice task is the probability given by the decision maker for the selected alternative. Confidence in judgment can be expressed, for a given probability p, by providing the limits of the interval (called a credible interval) that is thought to have probability p of containing the actual criterion value. (Further detail on confidence assess-

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ment procedures for both judgment and choice can be found in Lichtenstein et al., 1982, and Yates, 1990.) The Issue of Level. One problem that arises for research on confidence in groups concerns the locus of beliefs captured by the construct “group confidence.” One view is that some level of subjective uncertainty exists collectively for all of the group members-as if the group itself can think (Janis, 1972)-while another is that confidence exists only in the minds of individual group members. The debate about level of analysis will not be repeated here. (The interested reader is referred to thoughtful and comprehensive discussions of this issue in the contexts of group beliefs by Bar-Tal, 1990; and collective efficacy by Bandura, 1986; pp. 449-453.) The term Individual Confidence will be used to describe the confidence of an individual in his or her own decision. Similarly, the term Group Confidence describes the confidence of a group in its judgment or choice-an expression that is formed through the collective action of persons in the group. In this way Group Confidence is differentiated from the confidence of an individual member of the group in the group’s decision. The latter will be called Member Confidence. Notice that there is no necessary relationship between member confidence and group confidence.’ The classic illustrations of “Groupthink” (Janis, 1972) portray situations in which group confidence is inferred to be much higher than member confidence . ’ In this way, the paper takes the same position with respect to group confidence as it does for judgments and choices. That is, group members may or may not privately agree with either type of group product-the choice itself or the expressed confidence in it. Yet a decision that is produced by a group through interaction is considered to be a group decision. In a similar sense, an expression of confidence that is produced by a group through interaction is itself a group decision of sorts and can be considered to reflect group conlidence. If a group does not express overtly the level of confidence in its decisions, it is possible for the researcher to identify a level of confidence for the group by a summary statistic (e.g., median or mean) for the distribution of member confidence assessments. Here such an indicator would be referred to as Median Member Confidence or Mean Member Confidence. To avoid confusion, the term “group confidence” will be used exclusively for confidence assessments that are provided by the group itself. The rules that a group uses for determining a group judgment or choice, e.g., majority rules or consensus, are often explicit. Although confidence is not always explicitly expressed or subjected to rules for determining a single value for group output, it can be. For example, a group might use the median of its members’ confidence levels in reporting the group’s decision. In this case, Group Confidence is equal to Median Member Confidence as it would be computed by the researcher. Or, a group may discuss its uncertainty about its decision until it reaches a consensus confidence assessment. In this approach, group confidence is treated in the same way as group choice: both confidence and choice can be the same or different for individuals within the group and the group as a whole, and both may or may not be produced via formal rules, but are explicitly expressed as output from the group decision-making task.

128 Evaluating

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Group Confidence

The magnitude of group confidence is most useful if described in relative terms. Group confidence assessment data can be described with respect to three types of standards for comparison: (a) confidence assessments of independent individuals, (b) confidence of group members at points prior to and following the group decision, and (c) objective judgment or choice quality. Groups vs individuals. Using the first approach, group confidence assessments can be compared to those of independent individuals in an attempt to identify conditions in which groups are more or less confident than independent individuals. Put another way, groups and independent individuals can be located on a continuum of confidence at the conclusion of the decision-making endeavor. Confidence within groups. Also important are comparisons of confidence levels within a group at various points over the course of the decision-making process. This approach makes it possible to evaluate a group’s confidence at the point of the decision with respect to the preceding and subsequent levels of confidence of its members. For example, this approach allows us to learn whether the extent of group member confidence and group confidence are the same. Objective quality and appropriateness of confidence. It is sometimes possible to evaluate objectively the appropriateness of expressions of confidence. There are several important dimensions along which to appraise a set of subjective probabilities or credible intervals (see Yates, 1990), one of which is calibration. A prerequisite for evaluations of calibration is knowledge of the objective quality of judgments or choices. The objective data provide a standard for comparison so that researchers can determine the degree to which the level of confidence implied by a set of assessments is too high or too low. A set which shows neither overconfidence nor underconfidence is said to be well-calibrated. For example, a set of .90 credible intervals is well calibrated if 90% of the intervals contain the actual criterion value. Confidence assessments given for a choice task are well calibrated if the proportion of chosen alternatives that are in fact best is equal to the mean of the expressed probabilities. In situations in which objective decision quality cannot be known, group confidence can be described only in terms of its absolute level (i.e., how confident a group is), or its magnitude relative to confidence assessments from another source, such as from individuals. But with the availability of information about outcomes, group confidence can be described relative to the actual level of decision quality (i.e., how over- or underconfident a group is). The evaluation of the calibration of group conti-

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dence assessments allows us to understand more fully the implications of differences in group versus individual confidence. That is, we can ascertain the degree to which changes in confidence due to grouping parallel changes in objective judgment and choice quality. This approach will be used as much as possible in this paper. However, because a means of obtaining an objective evaluation of the quality of the group decision is a prerequisite for any diagnosis of over- or underconfidence, many laboratory and field studies of group decision making are not useful for evaluating the appropriateness of group confidence. Group decision tasks that concern values or preferences have only subjective criteria, e.g., the consensus of some referent group (Laughlin, 1980; McGrath, 1984). In such cases, a group may be considered to be successful if it reaches a consensus regarding preferences. But this form of success must not be confused with objective quality of the group decision itself. Other problems may prevent any evaluation of the appropriateness of confidence expressed by a group in its decision, even though objective criteria for quality can be defined. Understandably, field studies are plagued by problems of small sample sizes or lack of access to unambiguous outcome data in a timely manner. For these reasons, this attempt to describe and evaluate group confidence will center on research in which the decision outcomes are availableimmediately or eventually-to the researcher, but hidden from the decision makers at the time of their task (e.g., studies of difficult general knowledge tasks or real-time forecasting). The problems of obtaining objective evaluations of decision quality do hinder empirical research on decision making by groups. However, actual decision quality is-or should be-a critical component of group decision-making theory. THEORETICAL ISSUES CONCERNING GROUP EFFECTIVENESS Group confidence can be related to criteria of group effectiveness in recent influential models of group performance. Consider the three criteria in Hackman’s (1983) normative model of group effectiveness: (a) task output is acceptable to those who receive or review it, (b) the capability of members to work together in the future is maintained or strengthened, and (c) members’ needs are more satisfied than frustrated by the group experience. For decision-making groups, achievement of each criterion appears doubtful if group members become more uncertain, or if the group’s final confidence in its decision is low relative to some other meaningful standard (e.g., expectations for confidence in this task or the confidence of another group). The group with relatively low confidence in its decision will be less likely to find that decision acceptable to others, or to have an enhanced capability to make future group decisions. The effect of group confidence on attainment of the last criterion is most difficult to

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describe with any generality since it will depend on the number and types of members’ needs. But to the extent that people are motivated to reduce uncertainty, relatively low group confidence will be frustrating indeed. A similar argument can be made with respect to the satisfaction component of group effectiveness in Gladstein’s (1984) model of group behavior. If the task of a group is to choose a course of action, it seems odd to imagine that a group whose confidence is low (relative to a meaningful standard) could be satisfied with its decision. Of course, satisfaction is a more general term than confidence in choice. Group members could be satisfied with the process (or the fact that they reached some decision), but highly uncertain abut that decision. The Hackman and Gladstein models imply that an enhancement of confidence will generally be a desirable outcome of decision making by groups. But a critical issue that is not addressed in discussions of these models is whether an enhancement of confidence is generally desirable. Surely groups can become too confident given environmental reality. Just as for individuals, overconfidence in groups may be useful or it may be dangerous. But under some conditions, it might be wise to reduce group confidence. The question of whether high group confidence is a desirable outcome for decision-making groups has rarely been discussed. Perhaps this is merely a consequence of the lack of attention to the larger issue of actual performance quality in theory and in practice. The actual performance quality of decision-making groups is no less important than group confidence, yet actual performance quality is not given as an outcome of group interaction in either the Hackman or the Gladstein models of group effectiveness. Without the concept of actual decision quality, there can be no evaluation of group confidence or discussion about the appropriateness of that confidence. While normative models imply that enhancement of confidence through grouping is a positive outcome, some descriptive work suggests that it is inevitable. Groups may be used to make decisions as a strategy to gain commitment and acceptance of the decision by those who will implement them (Mason & Mitroff, 1981), presumably due to changes in the direction of increased confidence with grouping. Put more bluntly, groups may be used to make decisions for the purpose of increasing confidence in the decision-whether or not decision quality is improved. This is not necessarily undesirable. In many environments a shift toward greater confidence may be necessary to obtain certain organizational power tools, such as support (endorsement, backing, approval, legitimacy; Kanter, 1983)required for action. It is interesting that the assumption of increased confidence through grouping was embodied in such practices prior to the existence of a body of empirical research on group confidence that gives credence to such a belief. It is also disturbing that organizational theory

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and practice place great value on high group confidence, but show no concern for uppropria te group confidence. We now proceed to examine two theoretical perspectives-information processing and motivation-relevant to describing and evaluating group confidence in decision making under uncertainty. Available theory leads to competing hypotheses. There are compelling arguments for group interaction to reduce, or to increase, subjective uncertainty. Data from studies of group confidence in judgment and choice will be reviewed in light of these approaches. Included is a section addressing a topic closely related to group confidence-commitment to group decisions. The section closes with a discussion of the connection between group confidence and structured techniques for group decision making. THE INFORMATION PROCESSING PERSPECTIVE Independent

Individuals

vs Groups

Any study of decision making-group or individual-necessarily entails consideration of information processing, e.g., gathering and evaluating information or creating alternative courses of action (Guzzo, 1982). The view that individuals have limited capacities to process information (March & Simon, 1958) has become widely accepted; so too has the assumption that groups possess some degree of nonredundant information. Thus, group members collectively have more information available than does any individual (Stasser, 1988; Vinokur & Bumstein, 1974). Yet what is far less clear is the relative ability of groups to process available information. Steiner (1972) recognized that groups have the potential to enhance individual processes-as well as the potential to degrade them. The literature shows evidence of both. For example, Argote, Seabright, and Dyer (1986) compared individual and group use of individuating vs base-rate information and found that the tendency to rely on individuating information and ignore base rates was exacerbated by grouping. In other areas, data demonstrating both group process gain and loss have been found (e.g., for remembering of information in groups; Hartwick, Sheppard, & Davis, 1982). The variety of tasks, groups, and environments in such studies makes it difficult to draw general conclusions about the quality of information processing in groups. The following is an examination of the differences between individual and group information processing that are expected to affect subjective uncertainty. A brief review of research on individual information processing and subjective uncertainty is followed by consideration of the implications of this literature for group confidence. Anchoring and adjustment. Consider first a prominent explanation for the overconfidence typically expressed by individuals in their credible

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intervals for estimates of unknown quantities. Tversky and Kahneman (1974) proposed that individuals use an anchoring and adjustment process to construct credible intervals for estimates of quantities. First, one anchors on one’s estimate, then adjusts for subjective uncertainty about the actual value of the quantity. Because adjustment is typically insufficient, the intervals are too narrow. Such “overconfidence” in judgment is a robust phenomenon for individual judgment (Sniezek & Buckley, 1991; Slavic, Lichtenstein, & Phillips, 1982). Anchoring and adjustment is widely supported as a model of the judgment process (Cervone & Peake, 1986; Sniezek, 1988; Switzer & Sniezek, 1991). To the extent that confidence assessments are themselves judgments (of judgments), similar processes will be used to generate both. But do groups use an anchoring and adjustment process to make confidence assessments? If so, then group confidence assessments should be just as overconfident as individual confidence assessments. If comparable levels of overconfidence are not observed, then the process is not one of anchoring on the (group) judgment and adjusting for uncertainty. Or, it may be an anchoring and adjustment process that differs in the way that adjustments are made. Sniezek and Henry (1989) proposed what will be referred to here as the “competing anchors” hypothesis. This hypothesis predicts debiasing of credible intervals by using multiple judges with varying individual judgments. The logic is that the various judgments of the individual group members create multiple potential starting points for the group judgment. These multiple potential “anchors” preclude the use of the anchoring and adjustment heuristic since it would be necessary to first evaluate the multiple points to select a single anchor. By definition, such evaluation of multiple starting points is beyond the processing activity associated with this heuristic. Hence, any evaluation of the multiple points by the group would serve to debias individual overconfidence resulting from use of the anchoring and adjustment heuristic at the individual level. As a result, member confidence, and subsequently group confidence, in judgment would generally be lower than individual confidence. Domain of information processing. Another line of research on individual overconfidence in choice tasks explains the phenomenon in terms of the domain of information that is processed in the course of decision making. The resulting “domain of information processing hypothesis” leads to the prediction of reduced confidence for groups. A series of studies suggest that overconfidence in individuals is reduced by increased processing of information. Confidence has been significantly reduced by manipulations that require consideration of a greater number of alternatives (Ronis & Yates, 1987; Sniezek, Paese, & Switzer, 1990; Sniezek & Buckley, in press). Similarly, confidence has been found to be reduced by manipulations that require consideration of outcomes from

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the chosen alternative other than the anticipated outcome (Hoch, 1985; Koriat, Lichtenstein, & Fischhoff, 1980). If subjective uncertainty is assessed in similar ways for both groups and individuals, confidence should decrease with the increased information processing resulting from group members’ discussion of their varying individual perspectives. Disagreement among members. Both the “competing anchors” hypothesis for judgment tasks and the “domain of information processing” hypothesis for choice tasks predict reduced confidence with groups compared to individuals if two conditions hold. First, group members must have different judgments or choices. Second, group members must share and process those differences during interaction. Given this similarity between the explanations embodied in the “competing anchors” and “domain of information processing” hypotheses, subsequent discussion will use the more general name of the latter, but will pertain to both judgment and choice tasks. The first assumption is generally easy to verify. If members of a group began with consensus, there would be no task for the group to perform. With the types of problems generally tackled by groups-difftcult and immersed in uncertainty-there will be some disagreement among group members. Disagreement within the group is often guaranteed by the deliberate creation of heterogeneous groups through the selection of members, as in teams with members from various disciplines or groups whose members represent diverse segments of the population of interest. Also, research shows that disagreement is greater if group members form their own judgments independently, e.g., prior to the initiation of group discussion, than if they do so following some interaction (Sniezek & Henry, 1990). Even persons who have devoted extensive time and effort to the study of a problem-experts-often exhibit cognitive conflict (Hammond, Anderson, Sutherland, & Marvin, 1984). Disagreement within a group provides the opportunity for enlarging the domain of information processed, e.g., consideration of a wider range of alternatives or con as well as pro reasons for any given alternative. Because of this opportunity, the domain of information processing hypothesis implies that disagreement among group members has the potential to lead to information processing that reduces confidence and makes the group more realistic. Consistent with this reasoning, Starbuck (1976) hypothesizes that organizations are more realistic than individuals due to their greater opportunities for sharing of information and personnel with comparable organizations. But whether that potential is realized depends on actual sharing and consideration of the different inputs from members. Restrictions on domain. According to the domain of information processing hypothesis, disagreement among group members is necessary for increased uncertainty in group judgment and choice. However, disagree-

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ment is not sufficient. To expand the domain and thereby reduce confidence, members’ varying alternatives and reasons must be processed by the group. Or, in the language of Walsh, Henderson, and Deighton (1988), the negotiated belief structure of the group should have high realized coverage of members’ individual schema for the information domain. This assumption is far more tenuous than the first. Janis (1972) proposes that concurrence seeking in cohesive groups might inhibit information processing and result in poor decisions. Subsequent illustrations of “groupthink” have demonstrated how concurrence seeking can occur, but that is not to say that it is typical of decision-making groups in general. For individuals, the net effect of domain restrictions (e.g., selective retrieval of information favorable to a particular alternative) is increased confidence or, more often, overconfidence (Hoch, 1985; Koriat et al., 1980; Ronis & Yates, 1987; Sniezek et al., 1990). There is some evidence of similar bias in information selection in social settings. The recalling of information relevant to the decision has also been found to be biased by the apparent opinions of others (cf. Hartwick et al., 1982). Stasser and colleagues have investigated information pooling in decision-making groups and found that not all information potentially available to the group from its members is accessed. For example, Stasser and Titus (1985) distributed pieces of information about job candidates so that some information was given to all group members while other information was distributed to select group members. The shared information dominated discussion, with unique pieces frequently being ignored. Sniezek, Paese, and Furiya (1990) examined sharing of information, particularly prior independent individual judgments, in a replication of the risk estimation task of Sniezek and Henry (1989). Both videotapes and self-reports of group discussion were used to obtain data on the group process. Participants (n = 30) made independent estimates of the annual frequencies of deaths from each of 15 causes and provided 99% credible intervals for each estimate. In groups of size three, these same participants were instructed to produce consensus estimates and credible intervals for each of the 15 causes. Analyses of videotaped discussion revealed that no more than 32% of individual group members’ judgments were shared explicitly during discussion. This restriction on the domain of information processed occurred despite the fact that social pressures for conformity were minimal (i.e., the groups were ad hoc, not cohesive) and there were incentives for accurate group judgment (i.e., rewards were offered and given for high performance). Rank-order correlations were computed between group rank on accuracy and group rank on sharing across the 10 groups. The sharing of individual judgments was positively, but not significantly, related to accuracy. Similarly, sharing correlated positively with group confidence (p = .53, p < .12).

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From such studies it is apparent that information processing in groups can be flawed in the same manner as individual information processing. Despite the inhibitions to information sharing and processing in groups, disagreement (in the form of diverse judgments among members) has typically been associatedwith superior decision-making quality (Hogarth, 1978; Libby, Trotman, & Zimmer, 1987; Sniezek & Henry, 1989; Rohrbaugh, 1979). (An exception is provided by Walsh et al., 1988.) But it is clear that a failure of the group to confront the diversity of impressions within its membership not only will prevent the group from forming judgments and choices superior to those of individuals (Kiesler & Sproull, 1982), but will also prevent a reduction in (over)confidence. Interventions

Various attempts have been made to overcome information domain restrictions in social decision making. Some of these focus directly on expanding the domain of information processed in group interaction. Others-such as various group techniques for decision making-are intended to produce the same effect, though as an indirect result of controlling social processes in the groups. Range expansion. Sniezek and Paese (1989) used two manipulations designed to directly affect information processing of the group by extending the range of values that the group considered. Each manipulation was expected to improve both group judgment accuracy and calibration. Groups in all conditions were instructed to form consensusjudgments in the risk estimation task (from Sniezek & Henry, 1989). They randomly assigned 135 students to 45 ad hoc groups of size three. Each group was randomly assigned to one of four conditions in a 2 (Uncertainty vs No Uncertainty) by 2 (Input vs No Input) factorial design. All members of all groups began by forming independent individual estimatesof annual mortalities from each of the various causes of death. The Uncertainty manipulation required each group member to provide a 90 credible interval for each estimate. In the No Uncertainty conditions, only the estimates were made. Groups in the Input condition were given information about members individual estimates or credible intervals. Subjects in the No Uncertainty-Input conditions were provided with each of their group members’ prior individual estimates at the onset of group interaction. In the Uncertainty-Input condition, subjects were given the minimum and maximum of the limits from the set of three credible intervals. Groups in the No Input conditions were neither encouraged nor discouraged from sharing their individual judgments during group discussion. Observations of information pooling-or rather the lack of it-in the Sniezek et al. (1990) study suggest that fewer than 20% of individual judgments would be shared within groups in this condition.

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In terms of the magnitude of group confidence, results showed marginally significant effects of each of these manipulations to expand the domain of information available during group interaction. There was a marginally significant difference in group confidence between the Input and the No Input groups (F(1,44) = 2.88, p < . l), with a lower mean confidence (i.e., wider credible intervals) for groups given Input. The manipulation of setting credible intervals for judgments showed a similar effect. Groups in the Uncertainty condition, whose members provided credible intervals with their individual judgments, were somewhat less confident than the control groups (F(I ,44 = 2.96, p < . 1). The Uncertainty manipulation led to significant improvement in group judgment accuracy (as measured by mean log squared error between group judgment and criterion). Error in group judgment was significantly lower for groups whose members had previously set credible intervals for their judgments (3.42) than for those who did not (3.71; F( 1,43) = 9.51, p < .Ol). But there was reason to believe that this effect was originally an individual level phenomenon that was carried over to the group judgment. Mean (log squared) error for the initial individual judgments showed a significant difference in the same direction (3.82 vs 4.19; F(1,41) = 8.62, p < .Ol). Integrating the findings on group judgment accuracy and confidence in this study we find that groups whose members set credible intervals for their individual judgments were significantly more accurate, and marginally less confident, than control groups. This suggests that it is sufficient to expand the range of values considered by group members individually to get improved group judgment and reduced confidence. But calibration analyses reveal a benefit of combining both manipulations, i.e., expanding the range for individuals and making available to the group information about the expanded ranges. Groups in the Uncertainty-Input condition had significantly more of their consensus group 90 credible intervals (for their consensus group judgments) containing actual values (40%) than did any other condition (with means of 20-22%). Results of the Sniezek and Paese (1989) study show evidence of several benefits of manipulations designed to expand the range of information processed by group members individually and collectively. Controlling social factors. Alternatively there can be interventions in the social processes of groups to prevent social factors from interfering with processing of information in the group (Van de Ven & Delbecq, 1974). The group practice literature has recognized the lack of discussion of all group members’ perspectives as a potential problem limiting the quality of group performance. Several techniques have been recommended as remedies, such as devil’s advocacy, dialectic inquiry, delphi, and the nominal group technique. A failure to adequately process infor-

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mation available to the group as a whole will not only prevent process gains, but will also preclude any reduction of confidence. Thus it is concluded that the information processing approach leads to the prediction of reduced confidenceand reduced overconfidence-in groups compared to individuals if two conditions are met: (a) group members have more information collectively than each does individually and (b) this information is shared and processed during group interaction. While the first assumption will generally hold, the second may not. If it does not, then there will be no improvement in group judgments or decisions and no reduction of confidence. Those groups that do adequately process the divergent judgments, evaluations, reasons, etc., of their members are expected to produce better decisions-but be less confident and therefore generally better calibrated-than individuals. It is interesting that by the logic developed using the information processing approach, the samefactors that improve the quality of group decision making should also make groups more uncertain about their decisions. We turn now to a review of data on group decision quality and confidence. Group vs Zndividual

Confidence Data

Comparisons of groups and individuals lead to the general conclusion that groups are more confident. Confidence expressed in the form of credible intervals has been found to be higher for groups than individuals for concurrent judgments (Sniezek & Henry, 1989, 1990; Sniezek 8z Kolzow, in review; Sniezek et al., 1990)and judgmental forecasts (Sniezek, 1989).Groups have also been reported to be more confident in recognition tasks (cf. Hinsz, 1987).Chalos and Pickard (1985) reported more consistent judgment for groups than for individuals, which agrees with the foregoing results if one accepts that inconsistency is a manifestation of uncertainty. Contrary results in the form of lower confidence for groups than individuals have been reported by Tindale (1989)and Sniezek (1990), but only for one of five forecasting tasks. Where it is possible to assess objective quality of the group output, most studies show an improvement over that of individuals so that the higher confidence appears to be typically warranted in the studies showing it. Thus, the prediction developed from the information processing perspective above is not widely observed. In general, conditions that make groups more accurate than independent individuals also make them more confident. Whereas there are several studies showing that conditions that improve individual decision making decrease confidence, there is only one showing this for groups. Sniezek and Paese(1989)found that manipulations specifically intended to expand the range of information processing by groups simultaneously increased accuracy and reduced confidence.

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However, other research on factors affecting the level of confidence has shown similar effects for group and individual decision making, One such factor is task difficulty. Individual confidence calibration has been shown to vary with task difficulty so that people are typically underconfident in easy tasks and overconfident in difficult tasks (Lichtenstein et al., 1982). Sniezek (1990) studied judgmental forecasts and accompanying 50% credible intervals by groups given times series data for five economic and financial variables. The objective difficulty of the five tasks varied, with mean percentage error for individual forecasts ranging from 5.3 to 37.2%. Calibration data paralleled that for individuals: groups were calibrated in the moderately difficult task, underconfident in the easy tasks, and overconfident in the difficult ones. Of related importance is the finding that correlations between uncertainty (credible interval widths) and measures of forecast error were nonsignificant (and not always positive in direction). Confidence over the Course of Interaction Examination of confidence within groups involves comparisons of confidence levels of group members at various points prior to, during, and following group interaction. The uncertainty levels of group members prior to formation of a consensus decision are interesting because they have implications for the behavior of individuals in the decision-making group, and hence final group decisions and confidence. Individual group members’ levels of uncertainty at the start of the task have been postulated to affect various aspects of the group process. Several group theorists have hypothesized that individual confidence affects participation or influence in the group (Hastie, 1986; Sniezek & Henry, 1989; Steiner, 1972). Despite the compelling nature of the position, direct tests have found more support for participation (cf. Hastie, 1986) than influence (Seaver, 1979; Sniezek, 1989; Sniezek & Henry, 1989; Zalesny, 1990). The confidence of group members has also been thought to affect the criterion for consensus in the group (Davis, 1982; Hinsz, 1987). Hinsz found that the number of members required to support the correct response (for it to be chosen as the group response) decreased with increasing levels of confidence in the correct response. Hinsz notes that this finding is opposite to the prediction of Davis (1982) and suggests that higher confidence may lower the consensus criterion for choice due to the greater demonstrability that accompanies high confidence. Uncertainty has traditionally been a core concept in theories of group and organizational structure and functioning. For example, high uncertainty can affect group behavior such as centralization of communication and performance (Argote, Turner, & Fichman, 1989). Stasser and Davis (1981) took the position that changes in certainty

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during group interaction were purely the result of informational influence. This form of influence follows from arguments presented and thereby differs from normative influence, which follows directly from the decision preferences of other people in the group. Data on changes in confidence over time or situations have been relatively rare in empirical studies. Yet such a dynamic view of confidence in judgment and choice can be more enlightening than a static one (see Sniezek & Buckley, in press). A few studies taking a dynamic view of confidence in groups are discussed next. Sniezek and Kolzow (in review) attempted to track changes in individual confidence for 40 groups (of size three) in a judgment task requiring a group consensus estimate of an unknown criterion value (annual deaths due to motor vehicle accidents). At the start of the experiment, independent individual judgments and confidence assessments were obtained and used as a basis for formation of groups. Groups characteristics were varied with respect to two factors, each with two levels. Groups were composed on the basis of members’ initial expressions of confidence in their individual judgments and disagreement (i.e., variance) in those initial individual judgments. The result was a 2 (Confident or Uncertain) by 2 (Agree or Disagree) design. Groups in each condition were interrupted at regular intervals throughout the course of interaction and asked for a private reporting of each member’s current best individual judgment, as well as a rating of confidence in that judgment on a 7-point scale. In addition, individual judgments and confidence assessments were obtained after formation of a group judgment and group confidence assessment and disbanding of the groups. Confidence ratings from this study are illustrated in Fig. 1. It was generally the case that confidence for individuals and groups was higher

Confidence

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PreDisc.

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GROUP

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in the Confident condition than in the Uncertain condition. This is hardly surprising and merely shows a degree of consistency between the confidence that group members bring with them to the group task and the confidence that they express individually and collectively thereafter. But two deviations from this pattern are of particular interest. The first of these is at the prediscussion phase, which occurs after members have been informed of each other’s judgments, but before any discussion has taken place. Compared to mean confidence in the initial phase, mean confidence in the Agree condition at prediscussion has increased significantly (from 4.37 to 4.84), while in the Disagree condition it has decreased significantly (from 4.50 to 4.15; both p’s < .05). Mere information about the judgments of others in the group had the anticipated effects of elevating one’s own confidence if there was relatively little variance within the group but reducing it if the variance was great. Although it is well known that the effects of normative and informational influence cannot be completely disentangled (see McGrath, 1984, or Kaplan & Miller, 1983), these shifts in mean confidence of group members in their respective judgments appear to be largely the result of normative influence. So large was this influence that, regardless of initial individual confidence level, Disagree groups were significantly less confident (4.15) at the point of prediscussion (i.e., after seeing all members’ judgments but before any interaction) than were Agree groups (4.84; p < .05). Yet a different picture emerged from group confidence data. Subsequent to the sharing of judgments at the prediscussion phase, unrestricted interaction among group members permitted discussion of information pertaining to their respective judgments. The group confidence means for all four conditions surpassed the levels of confidence at both the initial and the prediscussion phases. Group confidence means paralleled initial confidence means in that, for both Agree and Disagree conditions, they were significantly higher for Confident groups than Uncertain groups (p < .05). Although group confidence did not differ between the two Uncertain conditions, it differed significantly for the Confident conditions (p < .05). At this phase of the task, the direction of the difference between mean group confidence for Confident-Disagree (7.70) and Confident-Agree groups (6.90) was opposite to that observed in the prediscussion phase. Although Confident-Disagree group members began interaction with lower mean confidence than they had as individuals prior to grouping, they expressed significantly higher group confidence than in any other condition. As seen in Fig. 1, members’ confidence levels for their final postgroup individual judgments were approximately 2 points higher than their respective levels of initial confidence in each condition; thus, differences between conditions paralled those at the initial judgment phase. Though

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the difference was not significant, final confidence in final individual judgments was somewhat lower than group confidence levels. Given that the group and final individual estimates and confidence assessments occurred in close proximity, data showing any drop in confidence from the group to the final phase raise some doubt about group members’ endorsement of the group confidence assessment. These data suggest two contributing factors in the level of confidence that groups have in their judgments. First, the relative level of confidence that group members held in their own individual judgments is apt to be similar to the relative levels of group confidence. But on average, the absolute level of group confidence will be significantly higher than was initial individual confidence. Second, resolution of disagreement that leads to a consensus group judgment in Confident groups is accompanied by a dramatic increase in confidence at the point of consensus. In Confident-Disagree groups, group confidence is higher than the level of members’ confidence at each previous phase, initial, prediscussion, and interaction. And, these groups were more confident than groups in any other condition. Turning to the latter parts of the group decision-making process, it becomes interesting to compare group confidence as it is expressed by the group as a whole with member confidence in the group judgment. However, such data are rare, making direct comparisons of member and group confidence difficult. Of related interest is the comparison of members’ independent individual judgments following the group task to the group judgment. Members who have low confidence in the consensus group judgment should generally deviate from the group judgment more when making postgroup individual judgments. Data on deviations between group and final individual judgments will be discussed in the subsequent section of the paper on commitment. Group Techniques and Confidence

There are data to show that the confidence a group has in its judgments or choices can be affected by the set of procedures directing the group’s decision-making process. Interaction with others can itself be a contributor to the elevation of confidence in groups. Rohrbaugh (1979, 1981) has suggested that (face-to-face) discussion may be necessary to create support for a consensus policy in cognitive conflict tasks (as opposed to other forms of communication). In a study of varying consensus requirements and information exchange rules for choice in a general knowledge task, Seaver (1979) found greater overconfidence with several forms of interaction among group members than for independent individuals. Ono and Davis (1988) report that group discussion leads to an increase in the certainty of sentence judgments. They diagnose two distinct processes

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that can lead to such a result: a change in belief strength about content or a reassessment of other members’ positions. Increased confidence through grouping may be partly attributable to the (explicit or implicit) goal of achieving consensus in the group. Consensus is a strong cue to accuracy. It may often be an invalid cue, but consensus is sometimes the best available surrogate for accuracy (as in much auditing research, for example). In a study of real-time judgmental forecasting, Sniezek (1989) found increased confidence with the discussion to consensus technique but not with the dialectic, delphi, or dictator (a.k.a. best member) techniques. However, Sniezek (1990) reported some evidence of wider credible intervals for the consensus technique than for staticized groups or the best member or delphi techniques. Over all techniques, consensus credible intervals were marginally better calibrated than those of individuals. This latter study has the unique feature of having task-relevant information shared by all group members prior to joining the group so that group performance without the opportunity for information pooling could be studied. Boje and Mumighan (1982) compared the effects of two structured approaches to group decision making, face-to-face or written feedback, to each other and to individual decision making. Both confidence and accuracy were dependent variables. Their data reveal a disturbing correspondence between judgment accuracy and the affective responses of group members over decision-making techniques. Although pooled individual estimates became more accurate over trials, the group estimates from the two procedures became less accurate over trials. Yet there was a significant main effect for confidence such that participants with the group procedures had higher confidence ratings. In addition, those with faceto-face feedback rated their procedure more highly and reported higher levels of enjoyment than individuals. As discussed earlier, satisfaction and confidence in group decision making are not equivalent concepts. Satisfaction is an attitude toward the task, process, group, or decision, while confidence is a belief about the quality of the decision. Nevertheless, it is informative to consider variations in satisfaction as a function of group technique. Gist, Locke, and Taylor (1987) speculated that methods such as devil’s advocacy and dialectical inquiry may yield higher quality results but lower levels of member satisfaction than consensus decision making. Schweiger, Sandberg, and Ragan (1986) compared consensus, dialectical inquiry, and devil’s advocacy in strategic decision making by groups. Though their measures did not directly assess subjective uncertainty, the results are similar to those of Boje and Mumighan. The consensus groups had lower quality recommendations, but expressed more satisfaction, a greater desire to

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continue to work together, and greater acceptance of group decisions than groups assigned the other techniques. It appears that there are tradeoffs between decision quality and member satisfaction to be made in choosing among various techniques for group decision making. It is worth noting that data illustrating a tradeoff have a resemblance to findings for group activities other than decision making. For example, teams with some problems of cohesiveness and member satisfaction have also been found to be those rated as the highest performers (Ancona, 1990). Vinokur, Bumstein, Sechrest, and Wortman (1985) report that satisfaction in teams of medical experts is more highly related to the process and information quality than to the outcome quality. A MOTIVATIONAL PERSPECTIVE By definition, more human resources are required for group than for individual decision making. Group members collectively tend to give greater time and effort to decision-making tasks than if any one of them completed it alone, and maybe even more than if each individual member completed the task alone. Theory and data both imply that greater time and effort exerted by groups (as for individuals, Festinger, 1957) will reduce their subjective uncertainty. Consider first the belief embodied in the “just world hypothesis:” rewards are allocated to persons in direct proportion to the extent to which they deserve them. Work harder; reap greater rewards. Mayseless and Kruglanski (1987) speculate that people may conclude that they are likely to be correct when they have “worked hard enough.” In general people may reason that spending more resources on a decision is likely to enhance the quality of the decision. This is often precisely the logic that is responsible for the use of groups to make decisions. Of course, such a policy is not,without merit. Up to a point at least, increasing the number of judges often does increase accuracy (Grofman, Feld, & Owen, 1984; Hogarth, 1978). Whether any improvement in accuracy justifies the accompanying increase in cost is another matter. Similar logic can be used for assessments of process quality and for process resource allocation. Research by Guzzo, Wagner, Maguire, Herr, & Hawley (1986) provides evidence that people hold implicit theories about the link between group process and performance quality. Through implicit theories, people use evaluative information about group interaction process to infer the quality of group outcomes. A more formal analysis of such beliefs can be accomplished through the theory of behavior in organizations proposed by Naylor, Pritchard, and Ilgen (1980). This theory, an elaborated version of subjective expected utility and expectancy-value theories, conceptualizes the beliefs underly-

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ing choice behavior as a series of perceived contingencies (between acts and products, products and evaluation, and evaluation and outcomes). Of particular interest is the perceived contingency relating acts (levels of time and effort allocation) to products (the results of the time and effort expenditure). Effort calculations can loom large in various aspects of the decision process (Bettman, Johnson, & Payne, 1990; Russo & Dosher, 1983). For any person in a given environment, this perceived contingency can be represented by a function relating time and effort allocation level to level of resulting product. Functions elicited from persons for a variety of tasks tend to have a positive linear form (Sawyer, 1990; Switzer & Sniezek, 1991). That is, people typically believe that product level increases as a direct result of increasing amounts of time and effort. This belief can be seen in Hackman’s (1983) normative model of work team effectiveness. This model proposes that effectiveness is a function of various factors, including the level of effort expended by group members. From this motivational perspective, group members can be expected to be more confident about their group judgments and decisions than their individual ones because group acts require higher levels of time and effort than individual ones. In practice, inferring the quality of products from the amount of resources allocated to the task may be reasonable, and even essential. But that does not necessarily mean that good group process guarantees good outcomes (Reagan & Rohrbaugh, 1990). Hence, these beliefs can contribute to inappropriate confidence. Commitment The ultimate contribution of research on confidence for decisionmaking theory and practice depends on the demonstration of consequences of confidence for decision-relevant behavior. If confidence assessments are shown to be unreliable or unrelated to one’s action following the decision, their recently acquired place in theory and research is not deserved. This point highlights the need to expand the set of measures beyond statements of strength of belief at the point of choice. One way to do this is to examine the persistence of confidence assessments over a range of postchoice situations. As illustrated at several points in this paper, it can be useful to know whether postgroup member confidence corresponds to group confidence. An alternative approach to commitment in decision-making groups is to compare reported levels of confidence in choice to subsequent behaviors. Both issues are related to the decision maker’s commitment to the selected course of action, and have been addressed in the group decision-making literature. Using the first approach, Sniezek and Henry (1990) examined consistency between group and member confidence. They defined commitment to the group judgment as the proximity of the group judgment to a sub-

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sequent independent individual judgment. To assess commitment, they obtained confidence assessments in a judgment task from groups as a whole, and then later from group members privately. Such multiple measurement could reveal any discrepancy between group members’ true beliefs about the quality of their group’s outcomes and those that they publicly professed in the social context of the group. Overall they found little difference between the two measures, leading to the general conclusion of high commitment as well as high confidence. However, differences in group confidence as well as commitment were obtained across varying conditions of individual judgment prior to the consensus group judgment. Groups whose members had not formed individual judgments prior to the consensus group judgment were more confident, but less committed than groups whose members had previously formed individual judgments. The confidence finding is consistent with the predictions from the information processing perspective because groups in the condition with the least opportunity to confront varying beliefs within the group had the least subjective uncertainty. Not only were the groups the most confident, they were also least committed. Thus, the high group confidence of groups that did not confront disagreement among members was relatively short-lived. Apparently the relatively lower group confidence resulting from resolution of explicit disagreement is more lasting. Similar measures of both member confidence and commitment were obtained in a study of handicapping judgments for race horses by Harmon and Rohrbaugh (1990). Their purpose was to compare the effects of two types of cognitive feedback intervention in a cognitive conflict task. Groups (of size three to six undergraduate students) were created on the basis of initial individual judgment policies to maximize intragroup disagreement. Groups in the full feedback condition were given lens model feedback for each member and encouraged to compare and contrast their policies. Group members in a condition of reduced feedback were given this form of cognitive feedback for only their own policies, and were not encouraged to share information during interaction. Although member confidence did not differ between these two conditions, member commitment did. Members of groups with full feedback had final individual judgment policies that were more similar to the policies formed by their groups. And, they showed greater evidence of learning. These data are similar to those of Sniezek and Henry (1990) in that group members with a greater opportunity to confront explicitly the disagreement within their groups prior to arriving at group decisions were more highly committed to those group decisions than control subjects. Of course, commitment in these studies has been defined narrowly to capture only differences between member and group confidence. Other conceptualizations of commitment in decision making would prove valu-

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able to understanding the importance of group confidence in decision making. One approach is simply to lengthen the time interval between elicitation of group and member confidence. Another is to examine behavior following the group decision. Such research should reveal a relationship between group confidence and behaviors such as actual allocations of time and effort to implementation of the group decision under conditions of high commitment. Escalation. A second line of research addressing commitment has been that on “escalation” phenomena, in which the decision maker responsible for selecting a course of action leading to negative consequences continues, or increases, commitment to that course of action (Staw, 1976, 1981). Research on escalation of commitment is particularly useful to understanding self-evaluation of decision making because it attempts to study behavior subsequent to a decision, - a future decision, not just beliefs. For this reason the phenomenon will be examined here in some depth. However, the decisions observed under controlled conditions tend to be hypothetical. Given that there are no consequences of choice for the decision makers, such demonstrations of escalation of commitment are no more revealing than elicitations of beliefs (as in confidence assessments). The potential significance of group-induced change in subjective uncertainty will be revealed in the behavior of decision makers-behavior that will affect the ultimate outcomes of the decision. Previous theorists have proposed that the need to justify one’s actions has an effect on subsequent behavior (e.g., see the explanation by Aronson, 1980). The self-justification construct has been used to explain the escalation of commitment phenomenon. Bazerman, Giulliano, and Appelman (1984) used dissonance (Festinger, 1957) and justification (Aronson, 1980) theory to predict that groups would show escalation of commitment. They presented two arguments for greater escalation in groups than individuals; however, this prediction was not supported by their data. Data from the Bazerman et al. (1984) study (of male students) revealed comparable patterns of escalation in individuals and groups of size four. As in the original escalation study by Staw (1976), subjects allocated significantly more funds to a division that was shown to be failing if they themselves had previously made the decision to allocate prior funds to that division (and thus had higher responsibility for the decision than if it had been made by others). Data on various dissonance measures support the assertion of Staw (1981) that dissonance processes underlie escalation of commitment. One of the measures was a rating of confidence in ability to make the correct (subsequent) decision. Confidence covaried with escalation for both individuals and groups-though not necessarily because group and individual escalation processes are qualitatively equivalent.

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Nevertheless the group decision-making unit has a unique potential to “debias” nonrational escalation of commitment. Bazerman et al. suggest that reducing group cohesiveness,e.g., by having different sets of group members responsible for initial and subsequent decisions, could inhibit the need to justify and result in diminished escalation. Escalation would be further reduced by conflict between the high-responsibility group members and the low-responsibility group members. The hypothesized relationship of conflict among group members and decision quality and escalation is consistent with the benefits of disagreement identified elsewhere in this paper. Clearly, more research in this area is needed to understand the implication of the escalation phenomenon for decisions made by groups. Given the prevalence of groups for important organizational and societal decisions, it is surely important to study in more detail the project determinants of escalation (i.e., factors that affect the financial value or utility of persistence versus withdrawal; Staw & Ross, 1987)from a social perspective. This could be accomplished by considering group effects on judgments of probability and utility. Another potentially useful approach is to expand consideration of the social determinants of escalation identified by Staw and Ross to include group process phenomena. Another theoretical perspective that can be used to explain group confidence in terms of motivational factors is given by Bar-Tal (1990). He argues that group beliefs define the essence of the group, and thus are held with high confidence, as facts or verities. When group membership is voluntary, . . . “the act of joining a group implies at least external acceptance of group beliefs” (p. 75). Bar-Tal’s analysis implies that the group identity created by sharing of beliefs is at risk if the group cannot reach a decision with confidence. Groups must always have some beliefs which are shared and held confidently; this consensus creates an inertia for confidence in the formation of subsequentjudgments and choices. Feedback and Group Confidence

People are known to seek out or create information about their performance quality when it is not readily available (Ashford, 1989). The confidence that a group has in its decision can be thought of as an evaluation of judgment and choice quality by the group itself. In the absence of objective outcomes or external evaluations, such confidence in choices made under uncertainty becomes the functional equivalent of feedback. As with feedback, confidence can be expected to have the effect of motivating and directing the behavior of both individuals and groups. But the consequencesof high confidence for individuals and groups will not necessarily be identical.

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Conlon and Barr (1989) identify several phenomena that may modify the effects of feedback when it is given in groups or other social contexts. One of these, social loafing, is relevant to this discussion. As Conlon and Barr point out, some data concerning the phenomenon of social loafing suggest that aggregated feedback (i.e., feedback about the group as a whole) will lead to lower levels of motivation in the group task (Latane, Williams, & Harkins, 1979). To the extent that group confidence functions similarly to group feedback, this line of research raises the possibility that group confidence will have more modest effects on subsequent group behavior than does individual confidence on individual behavior. In a similar vein, feedback effects in individual research may not apply to groups. Tindale (1989) compared the effects of various types of outcome feedback on individual versus group information processing. Several differences were apparent. First, overall confidence judgments for group members were lower than those for individuals. Second, increasing amounts of feedback reduced individual confidence while group member confidence was unaffected by feedback amount. And finally, group confidence decreased consistently over trials while individual confidence did not. Some wisdom gained from decision theorists concerning feedback is equally relevant to individuals and groups. Einhorn and Hogarth (1978) demonstrated the importance of environmental constraints on the availability of outcome feedback. Outcome feedback is potentially the most useful kind of information for achieving calibration. But in practice, information is not always informative. Even if outcome feedback is available, it is often difficult to evaluate the quality of judgments or decisions (Einhom, 1980). As in individual decision making, confidence in group judgment and choice can create a self-fulfilling prophecy. A group that believes in its decision may work harder to implement the chosen course of action successfully. Or, the group that expresses great confidence may receive additional support that improves the group’s chances for success. In this manner high confidence produces treatment effects than can be solely responsible for superior decision outcomes. A further problem is that it can be difficult to establish that group confidence has had a treatment effect on decision outcomes that surpasses the impact of actual decision quality. The result can be a cycle of reinforcement for high confidence in group decisions. CONCLUSIONS

Research cited here leads to the general conclusion that groups are more confident than individuals and that member confidence increases with group discussion. In these data, there has been little difference be-

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tween group and postgroup individual judgments. The similarity between group and immediately following member judgments suggests that an assessment of decision quality by the group is accepted by each member at the time that it is expressed. But further, direct comparisons of group confidence and member confidence in the group decision are necessary for a clearer picture of group members’ individual support for their collective expressions of confidence at the time that they are made. What is even more important but remains unknown is the extent to which members endorse the group confidence assessment--or the group decision itself-over time. In short, groups appear to be highly confident about their judgments and choices. In most-but not all-studies cited here, an increase in confidence through grouping has been justified since the objective quality of group judgments and choices is higher than that for individuals. To the extent that it is possible to draw conclusions about calibration, groups appear to be overconfident-but less so than individuals. To summarize the various influences on group confidence, it is useful to consider two components of group decision making conceptualized by Casey, Gettys, Pliske, and Mehle (1984): an informational component where groups generate information and a social component including both the additional information that arises during interaction and pure social factors. The information processing theory presented in this paper predicts a decrease in confidence but an improvement in decision quality if there is variance in the information held by group members and all information is shared and processed. Insufficient information processing can create overconfidence in groups just as for individuals. The failure to reduce confidence with grouping can be explained by incomplete evaluation of potentially available information. Techniques that directly expand the range of information processed by the group have shown some success in reducing judgment error while also lowering confidence (Sniezek & Paese, 1989). Information processing factors alone cannot explain why groups tend to be more confident than individuals working on the same judgment and decision-making problems. Social factors unique to groups-notably faceto-face discussion and the objective of reaching consensus-appear to contribute to high group confidence. The analysis of group confidence from the motivational perspective explicates the belief that good process leads to good outcomes. When groups are responsible for making a decision, considerable valuable resources are expended. The relatively greater cost of decision making by groups will appear to be justified if groups are also more confident. Comparison of independent individual confidence, member confidence, and group confidence is important for decision-making theory and re-

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search. To the extent that these confidence levels differ, the existing literature on confidence assessments for individuals cannot be generalized to many important decisions because it does not take into account the unique aspects of groups. But in comparing individual and group confidence in judgment and choice, the issue of generalizability from individual to group decision-making processes arises. Clearly, group and individual decisions in practice may differ with respect to decision importance, difftculty, environmental predictability, etc. Although these factors have been largely ignored in this paper, it is clear that such differences can make generalizability problematic. Further, there are many factors, e.g., cohesiveness, experience, hierarchical structure, time pressure, external support, that may influence the likelihood that a group will end up with a realistic appreciation of the uncertainties that exist. In summarizing research on any area it is often easier to say what is not true than what is true. First consider the observation that groups are often preferred over the individual in situations with great uncertainty and a higher need for quality. One possible reason is the alleged superiority of decision quality by groups; another is enhanced confidence. In response, two statements are offered as candidates for falsehood: 1. Group confidence is a surrogate for group decision quality. 2. Group decision quality is a surrogate for group confidence. The research discussed in this paper takes a clear stand on the criterion problem. Decision quality cannot be ignored. Obviously, objective evaluation is difficult and often impossible in many situations in which groups make decisions. But all criteria pose evaluation problems in practice. The potential measurement problems of obtaining data on actual decision quality should not preclude identification of decision quality as a critical outcome for decision-making groups. Group confidence may be a misleading indicator of decision quality, and vice versa. Confidence is conceptually distinct, and a major outcome of decision making. By observation of both decision quality and confidence, it is possible to learn how confident groups are about the quality of their decisions-as well as how confident they should be. In addition, it seems necessary for advocates of group techniques to explain the consequences of the practices for both group confidence and objective decision quality. Of particular value would be investigations into the consequences of group confidence of implementation of the decision. The single greatest issue concerning confidence in decision making for group practice is the ending point of groups under uncertainty. The recent, enhanced importance of groups in organizations (Drucker, 1988; Goodman, 1986) has stimulated new approaches to research on groups. One of those has been an increased emphasis on factors external to the group (Ancona, 1990). What remains unclear from this analysis is

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environmental factors that affect group confidence. But given that the subjective uncertainty of a group about its decision will affect the behavior of group members and others in the environment, group confidence research can contribute to an understanding of the relationship between a group and its environment. REFERENCES Ancona, D. G. (1990). Outward bound: Strategies for team survival in an organization. Academy

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