Full-Time and Part-Time Subgroup Differences in Job Attitudes and Demographic Characteristics

Journal of Vocational Behavior 55, 337–357 (1999) Article ID jvbe.1999.1686, available online at http://www.idealibrary.com on

Full-Time and Part-Time Subgroup Differences in Job Attitudes and Demographic Characteristics Robert R. Sinclair University of Tulsa

James E. Martin Department of Management and Organization Science, Wayne State University

and Robert P. Michel American Institutes for Research This study examined the hypothesis that subgroups of part-timers differ from each other and from full-timers in their demographic characteristics, organizational commitment, and other job-related perceptions. Frame of reference differences and differing patterns of relationship investments are thought to account for these differences. We examined these group differences using samples of 850 full-time and 1490 part-time unionized employees. The part-time subgroups included moonlighters (n 5 142), college students (n 5 365), people providing supplemental income to their family (n 5 661), and people whose part-time job was the primary source of income for their family (n 5 556). The results indicated other demographic differences in these subgroups and indicated subgroup mean differences in several job attitudes and perceptions. Further, results of a regression analysis indicated some group differences in prediction of organizational commitment. These findings suggest that researchers must rethink the relations between work status and organizational attitudes and behavior. Research and practice implications are discussed. © 1999 Academic Press Key Words: organizational commitment; job attitudes; part-time workers; work status; investment model; social exchange.

An earlier version of this article was presented at the annual conference of the Academy of Management, Organizational Behavior Division (June, 1997). Boston, MA. This article was supported by Local 951 of the International United Food and Commercial Workers Union and by faculty development Grant 13-2-1016163 from the University of Tulsa. The authors thank Dawn Borovsky and Ari Levi for their comments on issues related to this article. Address correspondence and reprint requests to Robert R. Sinclair, Ph.D., Department of Psychology, University of Tulsa, Tulsa, OK 74104. Fax: (918) 631-2833. E-mail: [email protected]. 337 0001-8791/99 $30.00 Copyright © 1999 by Academic Press All rights of reproduction in any form reserved.

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The economic, social, and political changes affecting organizations are well documented (Hartley, 1996). One outcome of these changes is that organizations now strive to be more flexible to adapt to continuously fluctuating market conditions brought on by global competition and instantaneous communication. To achieve this flexibility, organizations often reduce the size of their full-time and permanent workforce and increase their use of part-time and temporary workers. Such changes in human resource management strategies ultimately lead to changes in employee– employer relations (Rousseau & Wade-Benzoni, 1995). Because these changes are likely to continue and even accelerate, organizational scientists must develop more sophisticated models of their effects on organizational behavior and attitudes. Although organizational scholars have begun to compare full-time and parttime workers, much of this research assumes that part-timers are a homogeneous group (Feldman, 1990). The 1997 Teamsters strike against the United Parcel Service (UPS) illustrates the shortcomings of this approach. The Teamsters demanded increases in the numbers of part-time employees awarded full-time status. Although some part-timers strongly desired full-time work, internal UPS and government research indicated that the majority of UPS part-timers did not want full-time employment (Jones, 1997). It is clear from this example that different subgroups of part-timers exist. However, much of the existing research concerning work status ignores these differences. Thus, further research and theory are needed to understand (1) what subgroups of part-timers exist; (2) how and why these groups differ from each other; and (3) the consequences of these differences for employee– employer relationships. JOB ATTITUDE DIFFERENCES AND THE EMPLOYMENT RELATIONSHIP Affective organizational commitment is the psychological construct most commonly associated with the employment relationship. It refers to the employee’s emotional attachment to the employing organization and is marked by perceived value congruence and identification with the organization and a willingness to exert effort for it and a desire to remain a member of the organization (Meyer & Allen, 1984, 1997; Mowday, Porter, & Steers, 1982). Most commitment research draws on social exchange theory (e.g., Blau, 1964; Homans, 1974), which suggests that organizational attitudes and behavior are based, in part, on reciprocity for good or poor treatment by the organization (Levison, 1965). Because commitment reflects the quality of the employee– employer relationship, it is not surprising that more committed employees tend to report higher levels of health and well-being (Begley & Czajka, 1993; Meyer & Allen, 1997), have lower absenteeism rates and turnover intentions (Matheiu & Zajac, 1990; Tett & Meyer, 1993), perform their jobs more effectively (Mayer & Schoorman, 1992; Meyer, Paunonen, Gellatly, Goffin, & Jackson, 1989), and are more likely to engage in positive organizational citizenship behaviors (Hunt & Morgan, 1994; Shore & Wayne, 1993).

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Commitment and other job attitude constructs play a central role in our understanding of the psychological effects of employee– employer relationships. However, previous research suggests considerable ambiguity concerning work status differences in job attitudes. Some studies indicate that full-time employees are more committed to their employing organization than are part-timers (Lee & Johnson, 1991; Martin & Hafer, 1995), but others report no commitment differences (McGinnis & Morrow, 1990; Shockey & Mueller, 1994). Job satisfaction research indicates work status differences in satisfaction facets, but the direction of these differences is unclear (e.g., Bennett, Carson, Carson, & Blum, 1994; Eberhardt & Shani, 1984; Lee & Johnson, 1991; Levanoni & Sales, 1989; Logan, O’Reilly, & Roberts, 1973; Miller & Terborg, 1979). Similar studies report higher levels of job involvement for full-timers (e.g., Martin & Hafer, 1985; McGinnis & Morrow, 1990), while others report no work status differences (Werbel, 1985). Finally, several studies have examined withdrawal intentions and behaviors (e.g., turnover, absenteeism) among full-time and part-time employees. For instance, Martin and Hafer (1995) reported that part-timers had slightly stronger turnover intentions, but Bennett et al. (1994) and Smulders (1993) reported no relation between work status and absenteeism when other factors were controlled. Other studies suggest that variables such as marital status and job involvement moderate the relation between work status and withdrawal attitudes and behaviors (Lane, Mathews, & Prestholt, 1990; Werbel, 1985) or that work status moderates the relation between turnover intentions and behavior (e.g., Peters, Jackofsky, & Salter, 1981). Clearly, prior research is equivocal concerning work status differences in organizational attitudes and behavior. One reason for this equivocality is that much of this research defines part-time work status only by the number of hours employees work each week. As McGinnis and Morrow (1990) suggest, “operationalizing full vs part-time employment solely in terms of the number of hours worked may be overly simplistic if we are to fully comprehend how and why part-timers differ from full-time employees” (p. 95). Feldman (1990) argued that there are different subgroups of part-time employees and that researchers should focus on differences among part-timers under different work arrangements. He suggested that work arrangements can be arrayed on five basic dimensions: (1) permanent vs temporary, (2) organization hired vs agency hired, (3) year-round vs seasonal, (4) main job vs second job, and (5) voluntary vs involuntary. Feldman also suggested that people gravitate toward different types of work arrangements and, consequently, that subgroups of part-time employees have different perceptual maps and frames of reference for attitudinal variables such as commitment. Feldman and Doerpinghaus (1992) tested Feldman’s (1990) assertions with surveys in five organizations and found both demographic and perceptual differences among subgroups of part-time employees. Their results also indicated that part-timers use other part-timers in the same organization as equity referents. Other research evidence also implies systematic differences between part-timers

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under various work arrangements. For instance, Gannon and Nothern (1971) reported that long-term part-timers differ from short-term part-timers in intelligence, initiative, self-assurance, and perceived occupational level. Finally, other studies report attitudinal and/or demographic differences between moonlighters and nonmoonlighters (e.g., Bennett et al., 1990; Jamal, 1986; Pearson, Carroll, & Hall, 1994). These studies provide some support for the existence of systematic differences between subgroups of part-timers. EXPLAINING WORK STATUS DIFFERENCES: THE INVESTMENT MODEL Feldman’s research suggests that subgroups of part-timers use different frames of reference to evaluate organizations. Social exchange theory suggests that these differences explain why subgroups may react diversely to events in organizational life. Integrating these two approaches suggests that subgroups of parttimers develop different social exchange relationships with their employing organization because of their diverse frames of reference. Furthermore, the organizational and social context of work may vary dramatically for different groups of part-time employees. Rusbult and colleagues (e.g., Farrell & Rusbult, 1981; Rusbult, 1980, 1983; Drigotas & Rusbult, 1992; Rusbult & Farrell, 1983) provide a straightforward explanation for potential subgroup differences among part-time employees. Rusbult suggested that investments in romantic and/or organizational relationships can be characterized in terms of three broad dimensions: satisfaction with the relationship, perceptions of the quality of available alternatives, and the magnitude of the person’s investment in the relationship. These dimensions can be viewed as tapping affective, cognitive, and energic relationship investments. Rusbult’s research indicates that these variables explain job or task commitment, relationship commitment, and withdrawal behaviors such as break-ups in romantic relationships and turnover in organizations. The investment model can be applied to the UPS example described above. Some UPS part-timers were clearly long-term employees with a substantial investment in the organization, while others were students or housewives who sought short-term employment but were not particularly invested in or dependent upon the organization for the long run. In more general terms, the investment model suggests that organizational attitudes are influenced by the employee’s cognitive, affective, and energic investments in the employing organization. It follows that different subgroups of part-time employees develop different levels of investment in the organization and different patterns of organizational commitment and other job perceptions. This study extends Feldman’s (1990) work, suggesting that various types of part-timers gravitate toward different work arrangements. However, our approach differs from Feldman’s in how we identify relevant part-time subgroups. Feldman suggested that researchers study employees under different work arrangements. In the present research, we examine five subgroups of employees under one basic work arrangement, using configurations of “life circumstances”

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variables. The configurations included full-time employees; moonlighters who were working part-time elsewhere; college students who were working part-time while attending school; supplementers, defined as married employees contributing less than half of their family income from the job in question; and primaries, defined as employees who obtain most of their income from this job. We investigated differences among these groups on demographic characteristics, job-related attitudes and perceptions, and the relationship between these jobrelated attitudes and perceptions and organizational commitment. To investigate demographic differences, we compared the demographic profiles of a sample of full-time employees and four groups of part-time employees. We investigated work status differences in variables related to the employment relationship by examining mean and correlation differences in several variables across the work status groups. We examined mean differences by comparing each group on a set of eight variables that are commonly studied in the organizational commitment literature. We investigated correlation differences by comparing the explanatory power of the same set of variables with respect to organizational commitment in full-time employees and several groups of part-timers. METHOD Participants We used an archival data set to test our expectations concerning relationship dependence, work status, and organizational commitment (the original data was collected in 1983 and portions of the data appeared in Martin & Peterson, 1987). The original data set consisted of 2966 surveys of unionized retail employees of a large midwestern “supercenter” retailer (i.e., grocery and general merchandiser) with 109 locations across five states. The survey was sponsored by the union local representing these employees to assess job and union-related attitudes prior to bargaining a new contract. We used the employer’s assignment of each respondent as full-time or parttime to determine work status. Full-time work status referred to employees regularly working 40 or more h a week. Part-time work status denoted employees working less than 32 h a week. One important difference between these parttimers and the part-timers used in many other studies is the part-timers in the present sample were eligible for the same fringe benefits as full-timers, with the exception of dependent insurance coverage. Measures Organizational commitment. A three-item scale (e.g., “I am proud to tell others that I am a part of my employer’s organization”) developed by Martin and Peterson (1987) was used to assess organizational commitment. Each of the items was measured on a 7-point Likert scale, with scale anchors ranging from “Strongly disagree” to “Strongly agree.” These items tap affective organizational commitment and resemble items in the original organizational commitment

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questionnaire developed by Mowday, Porter, and Steers (1982) and more recent versions developed by Meyer and Allen (1984, 1997). Thacker and Fields (1986) reported a correlation of .94 between these items and the positively worded items in the original Mowday scale (personal communication cited in Martin & Peterson, 1987). Other, more recent work using these items includes Bemmels (1995), Magenau and Martin (1998), and Sinclair and Martin (1997). Predictors. The predictor set consisted of eight variables that are conceptually related to organizational commitment. The first was tenure, defined as the length of time the person had been with the organization. General Job Satisfaction was measured with a single item participants rated on a 7-point scale to indicate the amount of time (from “Never” to “All of the time”) that they are satisfied with their job. Two items were used to assess Quality of (employment) alternatives: “It would be very hard for me to leave this employer, even if I wanted to” and “It would be very difficult for me to find another job that is as good as the one that I have now.” These items closely resemble the concept of continuance commitment (Allen & Meyer, 1990). Employees with high scores on this scale believe that they have poor quality employment alternatives. A single item tapping Promotional opportunities asked employees to indicate whether they were fairly likely to receive a promotion in the next 2 years. This item used a 7-point agree– disagree response format similar to those described above. We also used a single item tapping the number of Grievances each employee had filed on his/her own behalf in the past 2 years. This item used eight response categories (none, 1, 2, 3, 4/5, 6 – 8, 9 –11, and 12 or more grievances). The “your own behalf” instruction was used to differentiate “self-interest” grievances from those filed by stewards on behalf of other employees. Labor–management relations climate was assessed using a scale developed by Rosen, Greenhalgh, and Anderson (1981). Participants described their views of the union–management relationship climate using eight bipolar adjective pairs (e.g., friendly– hostile, cooperative– conflicting). Pay equity was assessed using a three-item scale (cf., Martin & Peterson, 1987) in which respondents indicated how satisfied they were with their pay in general and whether they perceived their pay to be fair, both in comparison with other people in their unit and with other people doing similar work for other employers. The general satisfaction item used a 4-point scale (1 5 “Very satisfied” and 4 5 “Not at all satisfied”), and the other items used the same 7-point agree– disagree scale described above. Finally, Union commitment was assessed using three items rated with a 7-point agree– disagree response scale taken from Martin and Peterson (1987). These items parallel those used to assess organizational commitment and resemble the union loyalty scale developed by Gordon, Philpot, Burt, Thompson, and Spiller (1980). Identical union commitment items were used by Bemmels (1995), Magenau and Martin (1998), and Sinclair and Martin (1997). Demographics. The data set also contained several demographic questions used to form and describe the part-time subgroups. The questions used to form the subgroups included whether the employee had another full-time or part-time

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job, how many hours each employee worked in his/her current job, the percentage of total family income coming from the job, marital status, and whether the employee was currently enrolled in school. The questions used to describe the groups included gender, age, years of education, and whether the participant had any children living at home. Finally, each individual was asked a question with the stem “If I had my way I would work:” and the three response anchors “more hours here each week,” “less hours here each week,” and the “the same number of hours here each week.” Work status subgroup definitions. Because the employer guaranteed 40 h weekly to 80% of the full-timers, we eliminated the 264 employees who were working between 32 and 39 h each week to avoid confounding work status with hours worked. Then we used respondent demographic information to form the subgroups of part-timers. The first group consisted of 142 Moonlighters who were employed part-time at a second job. Employees were classified as (college) Students (n 5 365) if they reported being currently enrolled in college. Employees were classified as Supplementers (n 5 661) if they were married and less than 50% of their family income came from this job. Finally, employees were classified as Primary wage earners (n 5 556) if they earned over 50% of their total family income. We excluded an additional 348 part-timers either because of insufficient information (n 5 238) or because they fit into two groups that were too small to study— high school students (n 5 57) and moonlighters who were working full-time elsewhere (n 5 53). Thus, the final sample consisted of 864 full-time employees and 1490 part-time workers who fit into one or more of the four categories described above. There were varying degrees of overlap between the part-time groups (the proportions are displayed in Table 1). Of all the part-time employees, 45 were classified as both students and moonlighters, 56 were classified as both primaries and moonlighters, 31 were both students and supplementers, and 118 were both primaries and students. The supplementers did not overlap with either the moonlighters or the primaries. The lack of independence of these groups violates the assumptions of most group difference statistical tests. Therefore, where necessary, we relied on visual inspection of the data to identify relevant group differences. We believe that the statistical disadvantages of letting the groups overlap were offset by the fact that data obtained from these analyses are more generalizable than data obtained from artificially separated groups. RESULTS Demographic Differences for Participating Subgroups Table 1 presents demographic characteristics for each participant group. Compared with the full-timers, the part-time employees were more likely to be women, younger than 30, and earn over 50% of their family income from this job. Part-timers also were more likely to have completed some college education or to be currently enrolled in school. Part-timers also were less likely to be

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SINCLAIR, MARTIN, AND MICHEL TABLE 1 Participant Characteristics by Subgroup (in Percentages) a

Demographic characteristics Women 301 years old Any college education Currently in college Currently married Children living at home 50% 1 family income earned here Desires for hours More hours (%) Same hours (%) Less hours (%) Cross classifications b Moonlighters Students Supplementers Primaries

Full-time (n 5 864)

All part-time (n 5 1490)

Moonlighters (n 5 142)

Students (n 5 365)

Supplementers (n 5 661)

Primaries (n 5 556)

34.8 71.4 43.9 8.2 72.2 63.4 77.6

77.6 49.5 52.5 24.5 63.4 57.2 37.6

66.9 35.4 63.4 31.7 49.3 39.0 40.9

48.2 11.5 88.5 100 17.1 15.6 33.5

92.9 74.6 39.8 4.7 100 83.5 0

71.3 38.4 54.6 21.2 42.9 44.9 100

15.8 76.1 8.0

58.9 36.2 3.9

57.4 39.0 3.5

58.8 35.4 5.8

46.7 48.4 4.9

76.8 20.5 2.7

0 0 0 0

9.5 24.5 44.4 37.3

100 31.7 0.0 39.4

12.3 100 8.5 32.3

0.0 11.7 100 0.0

10.7 21.7 0.0 100

a The F tests of the group means on each variable suggested that the group proportions were significantly different for all variables ( p , .01); Student’s–Newman–Keuls post hoc tests indicated that most but not all subgroup means were different (these tests were not judged to be central to the article and were omitted for clarity). b Cross-classification figures indicate the number of people in the column group who were also in the row group; thus, 12.3% of the students were moonlighters and 31.7% of the moonlighters were students.

married and less likely to have children living at home. Table 1 also shows considerable demographic differences among the various groups of part-time workers. The majority of the moonlighters were younger women (66.9%) with some college education, about half of whom were married and 39% of whom had children. The students were split evenly by gender, and most were younger than 30, unmarried, and had no children. Most of the supplementers were women (92.9%), and most were over 30 (74.6%). Very few (4.7%) of the supplementers were currently in school, and less than half (39.8%) reported any college-level education. The majority of the primaries (71.3%) were women and most were younger than 30. Half reported completing at least some college courses, and 21.2% were currently in school. Slightly less than half (42.9%) were currently married and a similar proportion had children living at home. The demographic analyses support the hypothesis that different subgroups of part-timers have different patterns of demographic characteristics. Table 1 also presents the proportions of employees desiring more, less, and the same number of hours per week within each group. We noted five findings of

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interest in this data. First, relatively few employees in any group desired to work less hours (2.7 to 8.0%). However, the group with the smallest proportion of people who desired to work less hours was the primaries, and this is consistent with our definition of this group. Second, over three-quarters of the full-time workers desired no changes in the number of hours they worked, while less than 40% of the part-timers desired no changes. Thus, these data suggest that work schedule desires are an important distinction between full-time and part-time employees. The remaining three findings concerned comparisons among the different part-time subgroups. First, the data indicated that the primaries were the most likely to desire changes and that over three-quarters of the primaries desired increases in the number of hours they worked. Once again, this coincides with the definition of primaries. Second, despite the fact that the moonlighters and students had very different demographic characteristics, nearly 60% of each group desired more hours. Finally, the only group of part-timers in which less than half desired to work more hours was the supplementers. This finding supports the notion that supplementers are less interested in moving to full-time jobs than are other part-timers. We attribute this difference to their differing level of family responsibilities, although this is not directly implicated by these analyses. Taken as a whole, these data provide further support for our group definitions and some support for our distinctions among the different subgroups. Table 2 presents the means, standard deviations, and coefficient alphas for all scales within each group (the within-group correlations are not presented, but are available from the first author). The internal consistency estimates were adequate for company commitment (a’s ranging from .86 to .88), union commitment (a’s ranging from .77 to .83), and labor-management relations (a’s ranging from .91 to .94). The estimates for pay equity (a’s ranging from .62 to .68) and quality of alternatives (a’s ranging from .52 to .73) were lower than the .70 rule of thumb that is often used to assess internal consistency. Since low alpha estimates are a function of small numbers of items in the scales and low correlations between items (Cortina, 1993), we computed the average interitem correlations for pay equity and quality of alternatives. For pay equity the interitem correlations ranged from .44 to .50. For quality of alternatives, the interitem correlations ranged from .35 to .57, and all correlations except those of the moonlighters were above .40. These data suggest that the low internal consistency estimates for these scales are attributable to the low number of items in each scale rather than poor internal consistency. Mean Attitude Differences by Work Status We computed a series of t tests comparing the full-time and part-time means on each variable. The superscripts in the data column for all part-timers refer to these tests. These tests indicated that part-time workers were more committed to the company, more satisfied with their jobs and their promotional opportunities, and perceived higher quality alternatives elsewhere. Part-timers also had less

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SINCLAIR, MARTIN, AND MICHEL TABLE 2 Descriptive Statistics for Each Subgroup Full-time (n 5 864)

All part-time a (n 5 1490)

Moonlighters a,b (n 5 142)

Students a,b (n 5 365)

Supplementers a,b (n 5 661)

Primaries a,b (n 5 556)

Company commitment Mean Standard deviation Alpha

4.33 1.61 .88

4.75 F 1.46 .88

4.63 F 1.46 .88

4.45 P 1.47 .86

4.92 F,P 1.40 .88

4.64 F,P 1.52 .88

Job satisfaction Mean Standard deviation Alpha

4.51 1.41 n/a c

4.72 F 1.30 n/a

4.52 1.32 n/a

4.45 P 1.34 n/a

4.86 F,P 1.23 n/a

4.66 F 1.33 n/a

Quality of alternatives Mean Standard deviation Alpha

4.98 1.57 .73

4.78 F 1.58 .64

4.35 F,P 1.50 .52

4.21 F,P 1.59 .61

4.91 P 1.53 .62

4.91 P 1.59 .66

Tenure (years) Mean Standard deviation Alpha

10.49 5.11 n/a

6.05 F 4.42 n/a

4.88 F 4.20 n/a

3.76 F,P 3.36 n/a

6.96 F,P 4.66 n/a

6.27 F 4.13 n/a

Union commitment Mean Standard deviation Alpha

3.63 1.41 .77

3.65 1.32 .79

3.52 1.48 .83

3.57 1.33 .78

3.60 1.29 .77

3.68 1.36 .81

Labor–management relations Mean Standard deviation Alpha

3.56 1.12 .94

3.23 F 1.04 .93

3.31 F 1.00 .92

3.27 F 0.97 .91

3.23 F 1.05 .94

3.28 F 1.03 .93

Pay equity Mean Standard deviation Alpha

4.26 1.26 .67

4.36 1.24 .67

4.17 1.26 .62

4.09 F,P 1.18 .63

4.44 F,P 1.27 .68

4.24 P 1.21 .66

Promotional opportunities Mean Standard deviation Alpha

2.46 1.60 n/a

2.88 F 1.71 n/a

3.15 F,P 1.86 n/a

3.54 F,P 1.85 n/a

2.54 P 1.53 n/a

2.91 F 1.71 n/a

Number of grievances Mean Standard deviation Alpha

0.69 1.42 n/a

0.26 F 0.80 n/a

0.39 F 1.01 n/a

0.27 F 0.86 n/a

0.20 F 0.63 n/a

0.33 F 0.98 n/a

a

A superscript “F” indicates that the group mean was significantly different from the full-time workers. For comparison with all part-timers this was a t test ( p , .05) comparing the two groups. For the subgroups, this was based on a one-way ANOVA followed by post hoc tests comparing the mean of the full-time workers with the members of the subgroup and part-timers who were not members of the subgroup (Student’s–Newman–Keuls, p , .05). b A superscript “P” indicates that the part-time subgroup mean was significantly different from the mean of individuals who were not a member of that group. This is based on the same subgroup one-way ANOVA described above in the previous footnote. c n/a 5 single item scale.

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tenure and believed their labor–management relations climate to be poorer than the full-timers. Thus, part-timers were more committed and satisfied than fulltime employees, but had lower levels of investments in the relationship (i.e., they had spent less time with the organization and perceived better opportunities elsewhere). With respect to grievances, the part-timer mean was approximately one-half that of the full-timers. These findings probably reflect differences in the amount of time full-timers spend at work. Full-timers would be expected to be exposed to more grievable situations and not necessarily more likely to file a grievance over any single situation. Thus, these results replicate other research suggesting work status differences in job-related perceptions. Because not all of the subgroups of part-timers are independent of one another, we could not conduct traditional mean difference tests for all part-time subgroups. Therefore, we conducted four separate sets of one-way analyses of variance. Each of these analyses examined one variable in three groups: full-time employees, part-timers belonging to a subgroup, and part-timers who did not belong to that subgroup. Thus, one set of analyses compared full-timers, moonlighters, and nonmoonlighters; the second compared full-timers, students, and nonstudents; the third compared full-timers, supplementers, and nonsupplementers; and the fourth compared full-timers, primaries, and nonprimaries. In each case, we examined mean differences on company commitment, the three dependence measures, and the five predictors. These tests were all statistically significant ( p , .05) with the exception of the tests for union commitment. We followed each analysis of variance with a post hoc Student–Newman–Keuls test ( p , .05) to compare the means of the three groups. The results of these analyses are indicated by the subscripts in the data columns for each of the part-time subgroups. A superscript “F” denotes that the Newman–Keuls post hoc test was statistically significant ( p , .05) for the comparison between members of the part-time subgroup and the full-time employees. A superscript “P” indicates that the post hoc test was statistically significant ( p , .05) for the comparison between members of the part-time subgroup and all other parttimers. With respect to company commitment, all subgroups, except the students, differed from the full-timers. Further, all subgroups, except the moonlighters, differed from their respective comparison groups. Supplementers reported the highest levels of organizational commitment, students reported the lowest levels of commitment, and moonlighters and primaries reported similar levels to each other. These results support our expectations that different groups of part-timers develop different levels of commitment. The unexpected finding was the lower level of commitment for full-time employees as compared with part-timers (we address this finding in the discussion). Both supplementers and primaries reported significantly higher levels of job satisfaction than did the full-timers. The students reported lower levels of satisfaction than nonstudent part-timers and the supplementers reported higher levels of satisfaction than nonsupplementers. Several differences were noted

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concerning perceptions of quality of alternatives. Moonlighters and students perceived better employment alternatives than the full-timers. Further, moonlighters and students perceived better employment alternatives than primaries or supplementers. Not suprisingly, the part-timers had less tenure than the fulltimers; however, we noted several differences among the part-time groups. Students had less tenure than other part-timers and supplementers had significantly more tenure than other part-timers, but primaries and moonlighters did not differ from other part-timers. All subgroups reported similar levels of union commitment, and none were significantly different from full-time employees. Furthermore, all subgroups perceived a poorer labor–management relations climate and filed fewer grievances than did full-time employees, but none of the subgroups reported significantly different levels than did part-timers who were not in their subgroup. Some differences were noted with respect to pay equity and promotional opportunities. Compared with full-timers, students perceived pay equity to be lower and supplementers perceived pay equity to be higher. Compared with other part-timers, students and primaries perceived pay equity to be low and supplementers perceived pay equity to be high. The differences on this variable were smaller than those on some of the other variables. However, they support Feldman’s (1990) idea that these groups have different equity referents. More substantial subgroup differences were noted with respect to promotional opportunities. All groups except the supplementers perceived more promotional opportunities than did the full-time employees. Further, all groups except primaries differed significantly from their part-time counterparts. Students and moonlighters (as compared with other part-timers) perceived more promotional opportunities, and supplementers reported fewer opportunities. The primaries reported nearly identical levels as nonprimaries. These data support our assertion that the organizational context of part-time employment differs substantially depending on the particular type of part-timer under consideration. These differences include differences in levels of organizational commitment, job satisfaction and perceived quality of alternatives, pay equity perceptions, and promotional opportunities. On the other hand, few differences were noted concerning union commitment, labor–management relations climate, or number of grievances filed. Subgroup Prediction of Organizational Commitment To determine whether there were group differences in relations between the predictors and organizational commitment, we conducted a multiple regression analysis predicting organizational commitment from the set of predictors in each subgroup (see Table 3). The predictor set accounted for between 42 and 46% of the variance in organizational commitment in each of the subgroups. This finding suggests that, in general, the variables show very similar overall patterns of relations with commitment. This was also true for some of the individual predictors including union commitment (b’s ranged from .01 to .08), number of grievances filed (b’s ranged from 2.06 to .16), and tenure (b’s ranged from 2.02

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TABLE 3 Results of Multiple Regression Analysis Predicting Organizational Commitment in Each Subgroup Full-time (n 5 864) Multiple R R2 Adjusted R 2 Regression weights (standardized) Job satisfaction Quality of alternatives Tenure (years) Union commitment Labor–management relations Pay equity Promotional opportunities Number of grievances

Moonlighters (n 5 142)

Students (n 5 365)

Supplementers (n 5 661)

Primaries (n 5 556)

.66** .44** .44**

.68** .46** .42**

.66** .44** .43**

.64** .42** .41**

.68** .46** .45**

.39** .22** .02 .04 .24** .04 .16** 2.06*

.25** .04 .06 .04 .40** .17** 2.04 2.16**

.38** .23** .02 .01 .19** 2.01 .17** 2.08

.35** .24** 2.02 .08** .21** .06 .14** 2.08**

.37** .22** .02 .05 .24** .01 .12** 2.09**

** 5 p , .01. * 5 p , .05.

to .06). The most striking pattern of differences was for the moonlighters. Comparison of the magnitude of the beta-weights for this group with the same weights from the other groups suggested that job satisfaction was less strongly related to commitment and perceptions of labor–management relations were more strongly related to commitment. Further, contrary to findings in the other groups, promotional opportunities were not related to commitment and pay equity was related to commitment. Thus, moonlighters’ organizational commitment appears to be more strongly influenced by compensation and climate variables and less strongly influenced by advancement or alternative employment opportunities. DISCUSSION The purpose of this study was twofold. Our first goal was to extend previous research on part-timers by examining demographic and job attitude differences between full-timers and several subgroups of part-timers. The findings indicated several demographic and attitudinal differences between full-time and part-time employees and between several of the part-time subgroups. Our second goal was to examine whether organizational commitment was influenced by different variables for different groups of employees. The results suggested that the organizational commitment of moonlighting part-timers (i.e., those who held part-time jobs elsewhere) was influenced by different variables than that of other part-timers. Thus, in general, the results support our contention that part-time employees differ from full-time employees and from each other. We attribute these differences to varying frames of reference or levels of investments in the employment relationship.

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The use of an archival sample of unionized retail workers raises at least three possible generalizability issues. The first generalizability issue concerns the fact that the data were gathered in 1983. The age of the data set raises concerns about whether (1) the sample of employees is working in jobs or in conditions that no longer apply today, (2) the part-time subgroups we studied are no longer relevant, and (3) the constructs we studied are no longer relevant, and if the measures of the constructs and/or the expected patterns of relations among the constructs have changed enough that our results may not generalize to the contemporary or future work world. Regarding the first point, the key issues include identifying what changes have occurred and how these changes would influence our data. Our direct experience as consultants to the union representing the employees in the sample (first author, 3 years; second author, 18 years) suggests that the jobs we studied have not changed substantially since the data were collected. Obviously, social conditions and local labor market conditions have changed substantially in the past 15 years. In our view, whether (and how) these changes influence the answers to the types of questions we addressed is unknown and, ultimately, is a question for further empirical research. The second and third points can be addressed by considering other research on part-timers. Popular media reports and governmental data sources suggest that these part-time groups are at least as prevalent now or more so than they were at the time (cf. Feldman & Doerpinghaus, 1992; Jones, 1997; Presser, 1995). Further, the constructs we studied are still the subject of many research studies, and we know of no data that would suggest that changing social conditions would influence the definitions of these constructs or the relationships among them. Still, a clear need exists for replication of our specific results with more recent samples. A second generalizability issue is that the use of an archival data set placed constraints on our choice of predictor variables. Different results may be obtained by systematically sampling the predictor domain, perhaps using the social/ economic exchange distinction or some other framework to guide the choice of predictors. Finally, we acknowledge that unionized retail workers represent one region of the possible spectrum of jobs and employee– employer relations. Unionization creates a psychological and social context that influences employee– employer relationships (Hartley, 1995). The union may act as a mediating factor in many aspects of the employment relationship. Thus, the appropriate model for a unionized sample may differ from that of nonunion samples or samples of contingent workers. Future research should attempt to replicate and extend this study by examining employees in different occupations and employment settings. Subgroup Differences in Attitudes and Personal Characteristics This study indicates that part-time subgroups differ in systematic ways from full-time workers and from each other. We examined three types of differences between full-timers and part-timers and between subgroups of part-timers: demographic differences, job attitude differences, and predictors of organizational

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commitment. The most striking set of demographic findings concerned the differences between students and supplementers. The supplementers were nearly all married women who were over 30 years old with children living at home and low levels of college education. In contrast, the students were split roughly equally by gender and tended to be younger, single, and without children. These findings are not surprising, given the typical role expectations and constraints for members of these two groups, but they do call attention to the fact that parttimers should not be thought of as a single, intact psychological group. The analysis of group differences in job attitudes and perceptions provided further evidence of differences between part-timers and full-timers and between subgroups of part-timers. Each group appears to have its own set of reasons for working, role constraints, and employment relationship. These data might be used to construct common profiles of part-timers. For instance, the students and moonlighters tended to be less committed and less dependent on the employment relationship than were the supplementers or primaries. One interpretation of this finding is that the focal job was less central for the moonlighters and students, as both of these groups had a substantial involvement with another organization; the moonlighters were part-time employees of another company, and the students were attending school. The investment model is a useful framework for understanding how and why these groups might psychologically differ from each other. For instance, the mean differences in commitment might be accounted for by the groups’ varying levels of tenure and the findings that quality of alternatives and satisfaction predicted commitment. In any case, future researchers should develop direct measures of the investment concepts and test models of the relationship between these variables and organizational commitment processes. One promising direction would be to examine investment variables as mediators or moderators in social-exchange models of work attitudes and behaviors. Feldman suggested that the voluntary–involuntary dimension is one of the critical distinctions between groups of part-timers. One element of “voluntariness” for part-timers concerns whether the number of hours they are working is consistent with their desires. This study provides evidence for differences between full-timers and part-timers with respect to desires for more hours and this probably reflects differences in voluntariness. Very few of the full-timers wanted to change their hours while the majority of the part-timers desired increases. Once again, though, clear part-time subgroup differences emerged. Over threequarters of the primaries desired more hours, while less than half of the supplementers desired more hours. These data provide support for the concept that desired changes in the employment relationship are one distinguishing feature of different groups of part-timers. When coupled with the attitude differences among the subgroups of part-timers, these data suggest further support for the importance of this dimension. Other researchers discuss the distinction between contract makers who dictate the terms of an employment relationship and contract takers who accept the terms (see McClean-Parks & Kidder, 1994). Contract takers are thought to be relatively

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powerless in terms of control over the employment relationship. Voluntary part-time workers may feel more emotionally invested in the relationship because they have greater potential to be contract makers. That is, if the employment relationship turns sour it is easier for them to walk away because they have invested less and expect less from the relationship. Conversely, involuntary part-time workers are more likely to prefer increased opportunities and outcomes. To maintain cognitive consistency it follows that these individuals would lower their emotional investment in the relationship. Thus, the relationship among control, dependence, cognitive consistency, and commitment is likely quite complex. To understand this complexity, researchers may have to employ more sophisticated research designs (e.g., longitudinal studies) and perhaps more contextually rich research designs (e.g., qualitative designs or case studies). We did not expect that part-timers would report higher levels of commitment than their full-time counterparts. This finding held across three of the four subgroups of part-time workers. We believe that this finding is a function of the unionized sample and an indication of the effects of dependence. The part-timers had a similar benefits package and were paid on the same wage scale as the full-time employees. Thus, the compensation differences between these parttimers and full-timers are less pronounced than in other studies of part-timers. Further, the part-timers reported higher satisfaction, better perceived employment alternatives, and were less tenured. Finally, part-timers reported greater expectations that they were likely to receive promotions in the next 2 years. The full-timers may have “hit the ceiling” in terms of their advancement opportunities and consequently had diminishing future prospects. Thus, the situation we studied may represent a relatively unfavorable situation for full-timers and a relatively favorable situation for part-timers. Keeping in mind that these groups have different equity referents, it is not surprising that the part-timers reported higher levels of organizational commitment. Implications for Practice The present findings have several implications for practitioners. Organizations that rely heavily on part-time employees need to clearly understand who their part-timers are and incorporate this into their human resource management strategies. For instance, in the present sample, many of the part-timers have long-term relationships with the organization and some, but not all, of these employees seek more work hours and/or full-time work status. This is a very different managerial context than a situation where the part-timers are short-term, transitory, and have little or no interest in establishing a long-term relationship with the organization. Efforts to develop commitment are most likely more important for the longer-term employees. In the present sample, this would be most important for the primaries, as they are not only longer term part-timers, but are also likely to be the primary labor source for full-time employees. Finally, although efforts to build employee commitment are useful, such efforts are not a panacea and may not always benefit the organization or the employee. For

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instance, building commitment among transitory employees may have unanticipated morale consequences. Increasing employees’ psychological dependence on the organization as it currently exists may introduce new problems for large-scale organizational changes (such as reorganizations). Further, the intensity of employees’ reactions to such changes probably increases with greater levels of investment in the organization. Other human resource management practices are likely to be successful for different groups of part-timers. For instance, moonlighters, students, and supplementers are likely to face substantial extrarole conflicts of different sorts. Moonlighters have to contend with other jobs, students have to contend with school, and most of the supplementers probably have substantial parental responsibilities. Organizations using these types of employees have to understand and respond to each employee group’s unique sets of needs (e.g., schedule flexibility, child care). Further, intrinsic reward strategies (e.g., recognition programs) may work effectively for some groups but not for others. For instance, employees with a short-term and transitory employment relationship may only respond to extrinsic rewards such as more hours or wage increases. Long-term part-timers, because of their greater psychological investment in the organization, might respond to programs that acknowledge that investment. Future Research In our opinion, researchers interested in part-time employee work arrangements should pursue the following lines of research. First, efforts should be made to link this research with Feldman’s research on work arrangements. We envision a taxonomy/typology that links characteristics of the work arrangement with characteristics of part-time employees. Thus, we believe that research can be advanced by studying meaningful configurations of demographic variables rather than individual demographics in isolation. These configurations (student, moonlighter, supplementer, etc.) can occur whenever part-timers are employed, and the investment model suggests that there may be different attitudinal and behavioral consequences for people in each configuration. Second, research seems to be converging on a “core” set of psychological variables for understanding employment relationships. Feldman’s research suggests the importance of studying differences in part-timers’ evaluative frames of reference. Two important components of these frames of reference seem to be differences in equity referents and perceived control over the employment relationship. Our study suggests that relationship investments may be an important third dimension. One potentially fruitful direction for further research would be studies of the effects of future expectations on the organizational relationship. For instance, our findings concerning the group differences in perceived promotional opportunities suggest that employees’ expectations about their future likelihood of advancing in the organization may have distinct effects on organizational attitudes and behaviors. Further, future research should utilize direct measures of investments/ dependence and frames of reference and investigate these variables as possible

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mediators or moderators of the relationship between social exchange-based predictors and organizational commitment. Also, researchers should consider more complex relationships among these core psychological factors, such as nonlinear relationships or interactions among the variables. One useful direction would be to study how expectations evolve under different conditions of dependence and/or control. Finally, this study (and most previous studies of part-timers) focused on organizational attitudes. Further research should explore the behavioral consequences of psychological factors that influence part-timers employment relationships. The range of consequences under consideration should be expanded beyond traditional withdrawal and attachment behaviors. For example, when the economic consequences of exiting an unsatisfactory employment relationship are unacceptable, people have other options beyond psychological withdrawal. They may seek to restore equity by engaging in deviant behaviors such as sabotage and theft or by becoming poor organizational citizens. Such behaviors receive a great deal of attention in the job performance literature and researchers interested in work status and employee– employer relationships may benefit by incorporating them into their studies. For instance, researchers can consider whether commitment has different behavioral consequences for different part-timers. CONCLUSION Taken as a whole, the findings of this study support Feldman’s (1990) and McGinnis and Morrow’s (1990) assertions that it is important to consider why part-time and full-time employees might differ on relevant attitudinal variables. Part-timers often differ from full-timers in ways other than simply the number of hours worked per week. These differences include eligibility for benefit packages, involvement with other organizations, and economic dependence on income received from the position. Further, groups of workers differ in terms of the reasons they choose part-time work, their dependence on the work relationship, and the reasons for that dependence. Thus, it is no surprise that ambiguous and contradictory results are sometimes obtained regarding attitudinal differences between full- and part-time employees when the issue is examined simply in terms of number of hours worked. As this study demonstrates, an expanded conception of work status adds much to research efforts in this area. REFERENCES Allen, N. J., & Meyer, J. P. (1990). The measurement and antecedents of affective, continuance, and normative commitment to the organization. Journal of Occupational Psychology, 63, 1–18. Begley, T. M., & Czajka, J. M. (1993). Panel analysis of the moderating effects of commitment on job satisfaction, intent to quit, and health following organizational change. Journal of Applied Psychology, 78, 552–556. Bemmels, B. (1995). Dual commitment: Unique construct or epiphenomenon? Journal of Labor Research, 26, 410 – 422. Bennett, N., Carson, P. P., Carson, K. D., & Blum, T. C. (1994). A comparison of “traditional” and “atypical” workers: Demographic, behavioral, and attitudinal differences. Journal of Business and Psychology, 8, 467– 474.

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