- Email: [email protected]
The effectiveness of verbal prompts on sales
ARTICLE IN PRESS
Journal of Retailing and Consumer Services 13 (2006) 169–176 www.elsevier.com/locate/jretconser
The effectiveness of verbal prompts on sales Claus Ebstera,, Udo Wagnera, Sabine Valisb a
Department of Marketing, University of Vienna, Bruenner Strasse 72, A-1210 Vienna, Austria b Erste Bank der oesterreichischen, Sparkassen AG, Austria
Abstract The effectiveness of verbal prompts and prompting conditions on sales as well as the impact of the product ordered on the effectiveness of suggestive selling are investigated in this study. In a field experiment in two fast food restaurants, customers are exposed to suggestive selling, receiving differently worded prompts depending on the assigned experimental condition. Results show that in all treatment conditions, prompts lead to increased sales over the control group. Whereas no difference in sales is observed among the treatment groups, prompts in general are shown to be more effective in triggering the ordering of side dishes when used in conjunction with atypical main dishes recently added to the menu and when there is a fit between the main and the side dish. r 2005 Elsevier Ltd. All rights reserved. Keywords: Prompting; Suggestive selling; Sales promotion
1. Introduction Customer: A hamburger and a medium coke, please. Sales clerk: Do you want fries with that? While customers might not always appreciate it when a sales clerk responds to an order by suggesting a related item, such sales interactions seem to have become commonplace in many fast food restaurants. In saturated markets, in addition to acquiring new customers, marketers have been concentrating on increasing sales among their existing customers, encouraging them to buy more, to buy more often or to buy additional items. A sales promotion strategy frequently mentioned in practitioners’ literature is suggestive selling. This practice is defined as making a suggestion to potential buyers that they might have additional needs related to what has already been purchased (Rosenberg, 1995). Suggestive selling has been used in financial services (Andrews, 1999), retailing (D’Aversa-Williams, 2001) and catalog marketing (Lauderbaugh, 2002). Although Corresponding author.
E-mail address: [email protected] (C. Ebster). 0969-6989/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.jretconser.2005.08.003
the employees delivering scripted purchase suggestions might occasionally resent having to ‘‘push’’ products on their customers, as the suggestions made could come across as insincere or inappropriate (Leidner, 1993), anecdotal evidence suggests that suggestive selling can be a very effective method in increasing sales. In 1987, Martinko and, in 1989 Martinko, White, and Hassell demonstrated that suggestive selling could effectively increase sales. However, since then, little has been published on the effectiveness of suggestive selling in academic consumer behavior literature. As a result, this paper aims to examine the effectiveness of suggestive selling in fast food restaurants. Not only is the general effectiveness of suggestive selling investigated, but its use in conjunction with a variety of products as well as the effectiveness of different suggestion wordings is also examined. Furthermore, the potential influence of descriptive variables (e.g. gender and age of the customer, time of visit to the fast food restaurant, and location of the restaurant) is considered. Finally, given that the origin of this study is Austria and most practitioners’ reports on the effectiveness of this promotional technique originate from the US, it is also intended to assess whether
ARTICLE IN PRESS 170
C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
suggestive selling can effectively be implemented in a cultural context outside the USA.
2. Theoretical background to suggestive selling A conceptual background to suggestive selling can be found in operant psychology, a theoretical approach which has received renewed interest from consumer researchers in recent years (Foxall, 2002). Operant psychology focuses on directly observable behavior and was first introduced to a broader group of marketing researchers by Nord and Peter (1980) under the name of ‘‘behavior modification perspective’’. A basic assumption of operant conditioning is that people learn by producing changes in their environment. A central tenant of operant psychology is the antecedent–behavior–consequence (ABC) model. Antecedent stimuli (A) trigger behavior (B), which is followed by positive or negative consequences (C). These in turn influence the probability that this behavior will recur in the future (Skinner, 1969). According to the ‘‘law of effects’’ (Thorndike, 1911), if a behavior results in positive consequences, it will be repeated more frequently in the future. If followed by negative consequences, the likelihood of recurrence decreases. For example, in a fast food restaurant, antecedent stimuli—such as product displays, flyers, and recommendations from accompanying friends—might trigger customers to order a side dish. The customer’s satisfaction or dissatisfaction with the taste as well as a number of other consumption related factors determine the likelihood that the individual will reorder this side dish in the future. Prompts are a special type of antecedent stimuli, i.e. supplemental stimuli that help to initiate a desired behavior (Touchette and Howard, 1984). The desired response can be prompted in different ways. In a sales situation, gestural, physical, environmental and verbal prompts can be used. For example, to stimulate sales in a fast food restaurant, the salespersons could point to a dessert (gestural prompt) or hold a dessert tray in the customer’s direction (physical prompt). Illuminated boards over the sales counter and displays offering ‘‘specials’’ are examples of environmental prompts frequently used in fast food restaurants. When the staff in fast food restaurants offers customers items related to their original order, such as fries to go with a burger (cross-selling) or larger sizes (upselling), these suggestions can be considered verbal prompts. Verbal prompts were successfully used in social marketing to increase blood donations (Ferrari et al., 1985) and to encourage drivers to wear seatbelts (Engerman et al., 1997). In a services marketing context, verbal prompts were found to improve appointment keeping in a pediatric clinic (Friman et al., 1985).
Furthermore, verbal prompts were shown to increase sales of food and drinks in restaurants (Martinko, 1987; Martinko et al., 1989). Therefore, prompts might also be effective when cross-selling side dishes in a fast food restaurant. This leads us to propose Hypothesis 1: H1. The use of verbal prompts increases sales of side dishes. The specific wording of verbal prompts was found to be of particular importance in their effectiveness (Feeney et al., 1982). From informal discussions with managers and staff of fast food restaurants, we concluded that the effectiveness of prompting can be increased if prompts are delivered in a ‘‘forced choice’’ question, i.e. customers are prompted to order either one product or another. Support for the proposition that forced choice questions might lead to greater compliance with the request also comes from the ‘‘mindlessness principle’’ proposed by Langer et al. (1978). They found that for trivial, non-demanding requests, subjects avoid investing cognitive efforts and rely strongly on general knowledge structures. It is assumed that people are put into a state of mindlessness primarily in routine conversations that have frequently occurred in the past (Langer & Moldoveanu, 2000). Therefore, by wording prompts in a forced choice question format, consumers might feel obliged to choose one of two alternatives, resulting in more orders of the prompted product, as stated in Hypothesis 2: H2. The use of forced-choice verbal prompts is more effective in increasing the sales of side dishes than the use of regular verbal prompts. It seems probable that not only the wording of the prompts, but also the product that the customers are prompted to consider influence the effectiveness of prompting to a greater extent. We hypothesized that prompting would be more successful if the product prompted (i.e. the side dish) has a good fit with the main dish ordered. For example, in Austria, schnitzels (breaded pork/veal cutlets) are a national dish usually served with potato salad or fries. However, in Austria, unlike in the US, sandwiches are considered a light snack and are not usually served with a side dish. Accordingly, Hypothesis 3 states: H3. Prompting side dishes is more effective when consumers see a fit between the main dish and the side dish. Prompting is assumed to be a behavioral method used to initiate a behavior not previously shown (Kazdin, 1994). Therefore, it might be more effective to prompt customers to order a side dish with their main dish, if the
ARTICLE IN PRESS C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
main dish is a new addition to the menu rather than a dish traditionally ordered in a specific (type of) restaurant. The idea that prompting might be more effective when used in conjunction with dishes that customers are unlikely to have received previous prompting for, is supported by correspondent-inference theory (Jones and McGillis, 1976). This theory, which has been used by consumer researchers to explain some of the effects of price promotions (Lichtenstein et al., 1991), states that consumers are more likely to process and elaborate information when it is unexpected or unusual. When an event is unexpected, customers can no longer assimilate it into their existing knowledge structures, which may lead them to consciously examine their previous assumptions (Fo¨rsterling, 2001). This might happen, for example, when a customer orders a newly added item, such as a vegetarian dish for the first time, and is consequently prompted for the first time to order a side dish with this meal. According to correspondent-inference theory, behavioral observations are unexpected when the information is inconsistent with previous information or when it is distinct from other current information (Jones and McGillis, 1976). Consequently, restaurant patrons might respond more positively to suggestive selling when it is unlikely that they have been previously prompted to order a side dish with a specific main dish, or when they order a main dish not usually offered in a specific restaurant category. Accordingly, Hypothesis 4 states: H4. Prompting side dishes is more effective in increasing sales of side dishes when the main dishes are less familiar to customers in a restaurant. Further support for this hypothesis comes from the concept of perceived risk (Bauer, 1960), a customer’s subjective anticipation of loss from a product that does not provide all expected benefits (Roselius, 1971; Sweeney et al., 1999). Ordering an unfamiliar main dish or a main dish one has not tried in a restaurant might be somewhat risky for a restaurant patron. Ordering a side dish known to the customer together with the unfamiliar main dish might lower perceived risk as the customer is at least familiar with the taste and quality of the side dish, thereby increasing the likelihood of purchase upon exposure to a verbal prompt.
3. Method 3.1. Research setting In order to test the above hypotheses, an empirical research project was undertaken. We decided to use a causal design, and observation as the data collection method. A field experiment was conducted in an
171
Austrian fast food restaurant chain, specializing in a variety of schnitzels, but also serving sandwiches and chicken nuggets. Two weeks prior to the experiment, vegetarian and fish dishes, two product categories not offered by most Austrian fast food restaurants, were added to the menu. Data were collected over a period of 2 weeks in two branches of the chain. One was located in the food court of a shopping mall in a large city with a population of approximately 1,750,000, the other on the main street of a small town with approximately 10,000 inhabitants. Prior to the experiment, suggestive selling had not been used by the restaurant chain. 3.2. Design and procedure Before starting the experiment, the sales clerks of the two participating restaurants were trained in delivering the prompts to the customers. They were informed of the general nature of the experiment, but were blind to the specific hypotheses being tested. An after-only with control group design was chosen. Participants were assigned to one of four experimental situations based on the sequence of their arrival at the counter. Successive groups of ten customers ordering one of the main dishes offered (schnitzel, fish, vegetarian dishes, chicken nuggets, sandwiches) were assigned to one experimental condition. After having served the tenth customer, the next experimental condition came into effect. In experimental condition 1 (EG 1), customers were prompted to order potato salad with their main course. The wording of the suggestion was: ‘‘Would you like potato salad with that?’’ In experimental condition 2 (EG 2), they were prompted to order fries. Customers were asked: ‘‘Would you like fries with that?’’ In condition 3 (EG 3), a forced-choice question format was used to prompt the ordering of a side dish: ‘‘Would you like potato salad with that or would you prefer fries?’’ In condition 4, the control group (CG), no prompts were used at all. In order to determine the effectiveness of prompting by mere comparison of the experimental and control groups, suggestions to order a side dish were only used when patrons did not request it themselves, i.e. not all customers within the experimental groups were exposed to prompting. Data were collected at lunch time (11:30 a.m.–2:00 p.m.) and at dinner time (6:00 p.m.–10:00 p.m.). In both restaurants, there was only one cash desk, where customers ordered and paid for their food. An unobtrusive experimenter stood to one side, using differently colored cards to signal which experimental treatment the restaurant employee should adopt. The cards were attached to a rolodex-like device (visible only to the employee) and flipped to indicate a change in the experimental condition after ten customers. The experimenter recorded the main and side dishes ordered,
ARTICLE IN PRESS 172
C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
as well as the time of the sales interaction (lunch or dinner time) on a standardized observational form. The customer’s gender was also recorded and judgment was used to classify customers as children (below the age of 16) or adults. The customers were only observed but not interviewed in order to ensure an unobtrusive purchase situation and to exclude socially desirable response behavior.
4. Results 4.1. Effectiveness of verbal prompts—H1 The four groups were balanced with respect to location, time and size (each group contained 540 observations). A total of 2160 sales transactions were recorded in the course of the experiment, of which 1589 customers (74%) ordered side dishes with their main courses. The greatest percentage of customers ordering side dishes (79%) was in experimental group 1 (potato salad prompt), followed by 78% in experimental group 3 (potato salad and fries prompt) and 77% in experimental group 2 (fries prompt) (see Table 1). To investigate Hypothesis 1, the data from column 2 in Table 1 were used (i.e. experimental groups were pooled into a single category EG). The w2-test rejected independence between the experimental variable and the number of ‘‘side dishes ordered’’ (^w2 ¼ 59:1, 1 degree-offreedom, which corresponds to a p-level less than 0.01). This result is in line with intuitive interpretation of the data and clearly supports H1: prompted customers order side dishes more often, i.e. sales increased by a magnitude of about 17 percentage points. 4.2. Effectiveness of different prompting conditions—H2 Hypothesis 2 was analyzed by concentrating on the results of the three different experimental conditions (data from column 3, rows 3 to 5 in Table 1). The w2-test did not reject independence between the experimental variable and the number of ‘‘side dishes ordered’’ (^w2 ¼ 0:9, 2 degrees of freedom, which corresponds to a p-level greater than 0.1). This result is consistent with visual inspection of the data. Thus, the specific format of a verbal prompt, open or forced-choice question does
not appear to influence their effectiveness. Therefore, customers belonging to all three experimental groups were pooled into a single category called ‘experimental group’ (EG) for subsequent analyses. 4.3. Further descriptive analysis of the data In the previous section, it has already been argued that, besides prompting, there are a number of other potential influences on the probability of ordering a side dish. Preliminary examination of the situation at hand established ‘type of main dish ordered’ and ‘age of customer’ to be of relevance, the other variables being of minor (‘location of the restaurant’) or no importance (‘gender’, ‘time’). Looking at Fig. 1, four observations are apparent. (i) There is a consistent effect of the treatment variable. The percentages of side dishes ordered in the experimental group exceed the corresponding numbers for the control group in all cases. (ii) The type of main dish chosen matters. The five different options vary with respect to the frequency of side dishes ordered. There are two extreme cases. On the one hand, it is very popular to eat schnitzel with a side dish; while quite the opposite situation is evident for sandwiches, which seem to be preferred without accompaniment. Focusing on the results for the control group only, approximately the same number of patrons order side dishes with fish (69%) as with chicken nuggets (65%). (iii) Besides these disparities in magnitude, there is an impact on the effectiveness of prompting depending on the main dish chosen. This can be verified by looking at the differences between the percentages of EG and CG (these numbers are shown in Fig. 1). With the vegetarian dish, for example, about a 31-percentage point difference is found, whereas with chicken nuggets there is a 6-percentage point difference. Consequently, if analyzing the odds of ordering a side dish (versus not ordering a side dish) and comparing the odds for the two categories of the treatment variable (e.g. for the vegetarian dish), a score of 3.6, i.e. (66/(10066))/(35/(10035)) results. In both cases prompting is found to be less effective for chicken nuggets and sandwiches.
Table 1
CG: no prompt EG: prompt
Number/percentages of respondents ordering side dishes
Group size
329/61% 1260/78%
540 540 540 540 2160
1589/74%
427/79% 414/77% 419/78%
EG 1: potato salad prompt EG 2: fries prompt EG 3: potato salad and fries prompt
ARTICLE IN PRESS C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
173
Fig. 1. Differences in percentages between experimental group and control group.
(iv) The frequencies of side dishes ordered vary by age. Adults consume side dishes more often than children do. 4.4. Logistic regression analysis In Sections 4.1 and 4.2, only two variables at a time were studied by means of cross-tabulations. Section 4.3 has shown that other influences (e.g. age, main dish chosen) should be considered as well, and therefore, given the categorical character of the data, multiway frequency analysis was applied. Since the ‘‘number of side dishes’’ ordered is considered a dependent variable, logistic regression offers a convenient way to analyze the data. Therefore, a log-linear model is postulated to describe how ‘‘prompting’’, ‘‘age’’ and ‘‘main dish chosen’’ influence the probability of ordering a side dish. Because of observation (iii) in Section 4.3, the second-order effect /experimental stimulusmain dishS was additionally included. In mathematical terms, the model can be written as follows: ! Sd^ jkl ln 1 S d^ jkl ¼ const þ lEX j þ lAk þ lMDl þ lEX j nMDl þ ujkl with S d^jkl
estimated probability (percentage) that a side dish is ordered for cell (j, k, l);
effect of the experimental stimulus results are given in a relative sense, i.e. with respect to the reference category control group (lEX CG ¼ 0); je{EG, CG}; lA k effect of age results are given in a relative sense, i.e. with respect to the reference category child (lAchild ¼ 0); ke {adult, child}; lMDl effect of the main dish chosen results are given in a relative sense, i.e. with respect to the reference category sandwiches (lMDsandwiches ¼ 0); le {schnitzel, fish, vegetarian dish, chicken nuggets, sandwiches}; lEX j MDl second-order effect of experimental stimulus by main dish chosen; ujkl error term.
lEX j
Viewed as a special kind of multiway frequency analysis, our data is a 2225 table, with 2160 observations in total, distributed among the 40 cells. Furthermore, as there are only two observed cell frequencies with less than 5, the basic requirements for running a logistic regression are fulfilled. The results are presented in Table 2. By looking at the parameter estimates, significant influences for all independent variables are found. Since the parameter estimates describe the linear effects of the predictors on the log of the odds ratio of the outcome category, interpretation is more intuitive in terms of the
ARTICLE IN PRESS 174
C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
Table 2 Logistic regression: probability of ordering a side disha Independent variables
Parameter estimates 1.24 0.52 0.64 2.63 1.95
Odds ratio
Constant Experimental groupb Adultc Schnitzeld Fishd Vegetarian dishd Chicken nuggetsd Schnitzel experimental group Fish experimental group Vegetarian dish experimental group Chicken nuggets experimental group
0.49 2.11 1.12 0.98 0.77 0.33
1.68 1.90 13.80 7.04 1.64 8.21 3.06 2.68 2.17 0.72
Goodness-of-fit LR-test against ‘constant-only model’ LR-test against ‘full model’
w^ 2 ¼ 856:79 2 G^ ¼ 5:01
df ¼ 10 df ¼ 9
hit rate ¼ 84.2% (Cmax ¼ 73.6%e) r2 ¼ 0:34
N ¼ 2160 (Cpro ¼ 61.1%f)
‘Perfect model’ Pseudo-R2 (McFadden, 1974) Significant at the 10% level. Significant at the 5% level. Significant at the 1% level. a
Reference category: no side dish ordered. Reference category: control group. c Reference category: child. d Reference category: sandwiches. e Benchmark maximum chance criterion. f Benchmark proportional chance criterion. b
coefficients’ odds ratio (i.e. expðl^ Þ). For example, a customer choosing fish as a main dish is seven times more likely to order a side dish than a person having sandwiches. It can be noted that ‘‘main dish chosen’’ is the most influential regressor. Moreover, adults consume side dishes almost twice as often as children. The reasons for this are numerous. For example, children do not eat as much as adults and, therefore, are satiated with less food and do not need side dishes to satisfy their appetite. In addition, children probably have more restrictions on money at their disposal and, therefore, cannot afford to buy a side dish (even if they wanted to). When accounting for other effects, prompting is nevertheless found to have a significant influence, i.e. the odds of ordering a side dish are 1.68:1 in this case (whereas a rough estimate of the odds based on the data in Table 1 would be 2.27:1, i.e. (0.78/0.22)/(0.61/.039)). This result is in line with the approximation of the odds of ordering a side dish when belonging to the experimental group and ordering the vegetarian dish. In comment (iii) of Section 4.3 a preliminary estimate of 3.6 was derived which has to be compared with the estimate of 2.17 in Table 2. Simultaneous consideration of several effects reduces the magnitude of individual effects when looked upon in isolation.
Goodness-of-fit is also satisfactory. Statistical testing rejects the assumption that a constant-only model fits as well as the proposed one, but does not reject the full (i.e. saturated) model. Classification based upon the model fails only in about 16% of the cases (due to limited data, it was not possible to divide the data into an estimation and a hold-out sample to provide a more stringent calculation of the hit rate). A detailed analysis of the standardized residuals shows that all of them are smaller than 1.1 (in absolute value), and therefore there are no outliers in the data. Finally, pseudo R2 (McFadden, 1974) is also acceptable, enabling us to conclude that logistic regression provides results which are face valid as well as statistically sound. In accordance with preliminary results, the proposed model outperforms alternative formulations (with other independent variables such as ‘‘gender’’, ‘‘location of restaurants’’ or ‘‘time’’). 4.5. Investigation of H3 and H4 With respect to Hypotheses 3 and 4, it is interesting to observe the estimates of the interaction variable, e.g. prompting a patron who orders a schnitzel is three times more effective than if he were to ask for sandwiches (or
ARTICLE IN PRESS C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
chicken nuggets). Bearing in mind that schnitzels are usually served with a potato-based side dish in Austria, the significance of this parameter supports Hypothesis 3. The second-order effect is also significant for fish and the vegetarian dishes, although the odds ratios are slightly lower. In view of the rather similar percentages of side dishes ordered within the control group for fish and chicken nuggets (c.f. remark (ii) in Section 4.3 above), the increased effectiveness of prompting with fish dishes must be due to some external influence not considered until now. We attribute this to the fact that fish dishes have only been added to the menu recently, but concede that causality (in the strictest sense) has not, as yet, been established. Similarly, when comparing the vegetarian dish and sandwiches, the same pattern is identified, however, to a lesser extent. Subsequently, results are in line with Hypothesis 4.
5. Discussion This study examined the effectiveness of suggestive selling using verbal prompts. It has been shown that verbal prompts can lead to significant increases (16–18 percentage points) in sales of side dishes in fast food restaurants. This finding is consistent with the results of studies conducted in social marketing. Moreover, the hypothesis based on correspondent-inference theory, whereby prompts are more effective in increasing sales of side dishes when used in conjunction with behavior not previously performed, i.e. ordering side dishes with main dishes atypical for the restaurant, is supported by the results. However, the wording of the prompts did not appear to influence their effectiveness, and in particular the forced-choice prompt was not found to be more effective than regular verbal prompts. A possible explanation for this might be that both side dishes prompted were potato-based food items. While the results suggest that both fries and potato salad are highly popular with the restaurants’ patrons, it seems unlikely that the particular phrase used to suggest a side dish might have led customers who dislike potato-based dishes to overcome their dislike. 5.1. Limitations and areas for future research While this field experiment has demonstrated that verbal prompts are effective in fast food restaurants, caution should be exercised in generalizing these findings to other settings. Furthermore, correspondentinference theory can only partially explain the effectiveness of prompts. In the course of this study, it was not possible to conclude how effective prompts should be worded, a relevant issue for consumer researchers and practitioners alike. Further studies to investigate whether the effectiveness of suggestive selling can be
175
extended to related industries, and which factors, apart from the typicality of products, are influential, are warranted. An important factor in the effectiveness of suggestive selling might be whether a functional or hedonic product is being prompted. This distinction has been shown to influence price sensitivity (Wakefield and Inman, 2003) and could also extend to sales promotion effectiveness. Furthermore, further research could examine the role of social influence on the effectiveness of prompts. While only single orders (i.e. customers ordering one meal) were included in the present study, the effectiveness of prompts when multiple orders are placed and when customers order as part of a group, should be examined in future studies. Finally, it might be worth investigating the long-term effects of verbal prompting, and its impact on customer satisfaction and store loyalty. 5.2. Managerial implications From a managerial standpoint, it should be noted that verbal prompts could be a promising and costefficient sales promotion tool. Nevertheless, it should not be forgotten that prompting could lead to resistance from both employees and customers. Therefore, special care should be taken to overcome this reactance. To mitigate employees’ reactance to prompting, clear rules as to when sales should be prompted should be given, while at the same time allowing staff to use discretion when not to prompt (e.g. in the case of regular customers, fellow employees or children). In an empirical study, Johnson and Masotti (1990) found that behavioral interventions such as feedback, goal setting and positive reinforcement by management can increase appropriate suggested selling by employees. To minimize customers’ annoyance when prompted for additional purchases, prompting should only be encouraged with items complementing the purchase and prompts should be delivered in a courteous, non-demanding way. In conclusion, prompts can only achieve their full potential, if they are integrated in overall human resource and sales training strategy. Nevertheless, they can be a very valuable marketing tool. In fact, as a result of the obvious effectiveness of verbal prompting and its efficiency compared to alternative sales promotion instruments, such as price promotions, the fast food company involved in this experiment has been using suggestive selling ever since.
Acknowledgements The authors wish to thank two anonymous reviewers for their valuable comments on an earlier version of this article.
ARTICLE IN PRESS 176
C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
References Andrews, K.J., 1999. Extending upselling and cross-selling efforts. Target Marketing 22, 36–40. Bauer, R.A., 1960. Consumer behavior as risk taking. In: Hancock, R.S. (Ed.), Dynamic Marketing for a Changing World: Proceedings of the 43rd Conference of the American Marketing Association, pp. 389–398. D’Aversa-Williams, T., 2001. Merchandising+suggestive selling ¼ accessory sales. Sporting Goods Business 34, 44. Engerman, J.A., Austin, J., Bailey, J.S., 1997. Prompting patron safety belt use at a supermarket. Journal of Applied Behavior Analysis 30, 577–579. Feeney, E.J., Staelin, J.R., O’Brien, R.M., Dickinson, A.M., 1982. Increasing sales performance among airline reservation personnel. In: O’Brien, R.M., Dickinson, A.M., Rosow, M. (Eds.), Industrial Behavior Modification: A Management Handbook. Pergamon Press, New York, pp. 141–158. Ferrari, J.R., Barone, R.C., Jason, L.A., Rose, T., 1985. The use of incentives to increase blood donations. Journal of Social Psychology 125, 791–793. Fo¨rsterling, F., 2001. Attribution: An Introduction to Theories, Research, and Applications. Taylor & Francis, Philadelphia, PA. Foxall, G.R. (Ed.), 2002. Consumer Behaviour Analysis: Critical Perspectives on Business and Management. Routledge, London. Friman, P.C., Finney, J.W., Rapoff, M.A., Christophersen, E.R., 1985. Improving pediatric appointment keeping with reminders and reduced response requirement. Journal of Applied Behavior Analysis 18, 315–321. Johnson, C.M., Masotti, R.M., 1990. Suggestive selling by waitstaff in a family style restaurant. Journal of Organizational Behavior Mangement 11, 35–54. Jones, E.E., McGillis, D., 1976. Correspondent inference and the attribution cube: a comparative reappraisal. In: Harvey, J.H., Ickes, W.J., Kidd, R.F. (Eds.), New Directions in Attribution Research, vol. 1. Erlbaum, New York, pp. 389–419. Kazdin, A.E., 1994. Behavior Modification in Applied Settings, fifth ed. Brooks/Cole Publishing, Pacific Grove, CA. Langer, E.J., Moldoveanu, M., 2000. Mindfulness theory and the future. Journal of Social Issues 56, 129–139.
Langer, E.J., Blank, A., Chanowitz, B., 1978. The mindlessness of ostensibly thoughtful action: The role of ‘‘placebic’’ information in interpersonal interaction. Journal of Personality and Social Psychology 36, 635–642. Lauderbaugh, J.J., 2002. Embracing the upsell: Increase sales by shifting your phone reps’ mindset from service to sales. Catalog Age 19 (6), 49–50. Leidner, R., 1993. Fast Food, Fast Talk: Service Work and the Routinization of Everyday Life. University of California Press, Berkeley, CA. Lichtenstein, D.R., Burton, S., Karson, E.J., 1991. The effect of semantic cues on consumer perception of reference price ads. Journal of Consumer Research 18, 380–391. Martinko, M.J., 1987. An O. B. Mod. analysis of consumer behavior. Journal of Organizational Behavior Management 8, 19–43. Martinko, M.J., White, J.D., Hassell, B., 1989. An operant analysis of prompting in a sales environment. Journal of Organizational Behavior Management 10, 93–107. McFadden, D., 1974. Conditional logit analysis of qualitative choice behavior. In: Zarembka, P. (Ed.), Frontiers in Econometrics. Academic Press, New York, pp. 105–142. Nord, W.R., Peter, J.P., 1980. A behavior modification perspective on marketing. Journal of Marketing 44, 36–47. Roselius, T., 1971. Consumer ranking of risk reduction methods. Journal of Marketing 35, 56–61. Rosenberg, J., 1995. Dictionary of Retailing and Merchandising. Wiley, New York. Skinner, B.F., 1969. Contingencies of Reinforcement: a Theoretical Analysis. Prentice-Hall, Englewood Cliffs, NJ. Sweeney, J.C., Soutar, G.N., Johnson, LW., 1999. The role of perceived risk in the quality-value relationship: a study in a retail environment. Journal of Retailing 75, 77–105. Thorndike, E.L., 1911. Animal Intelligence. Macmillan, New York. Touchette, P.E., Howard, J.S., 1984. The effects of verbal performance descriptions on nonverbal operant responding. Journal of the Experimental Analysis of Behavior 54, 273–291. Wakefield, K.L., Inman, J.J., 2003. Situational price sensitivity: the role of consumption occasion, social context and income. Journal of Retailing 79, 199–212.
Journal of Retailing and Consumer Services 13 (2006) 169–176 www.elsevier.com/locate/jretconser
The effectiveness of verbal prompts on sales Claus Ebstera,, Udo Wagnera, Sabine Valisb a
Department of Marketing, University of Vienna, Bruenner Strasse 72, A-1210 Vienna, Austria b Erste Bank der oesterreichischen, Sparkassen AG, Austria
Abstract The effectiveness of verbal prompts and prompting conditions on sales as well as the impact of the product ordered on the effectiveness of suggestive selling are investigated in this study. In a field experiment in two fast food restaurants, customers are exposed to suggestive selling, receiving differently worded prompts depending on the assigned experimental condition. Results show that in all treatment conditions, prompts lead to increased sales over the control group. Whereas no difference in sales is observed among the treatment groups, prompts in general are shown to be more effective in triggering the ordering of side dishes when used in conjunction with atypical main dishes recently added to the menu and when there is a fit between the main and the side dish. r 2005 Elsevier Ltd. All rights reserved. Keywords: Prompting; Suggestive selling; Sales promotion
1. Introduction Customer: A hamburger and a medium coke, please. Sales clerk: Do you want fries with that? While customers might not always appreciate it when a sales clerk responds to an order by suggesting a related item, such sales interactions seem to have become commonplace in many fast food restaurants. In saturated markets, in addition to acquiring new customers, marketers have been concentrating on increasing sales among their existing customers, encouraging them to buy more, to buy more often or to buy additional items. A sales promotion strategy frequently mentioned in practitioners’ literature is suggestive selling. This practice is defined as making a suggestion to potential buyers that they might have additional needs related to what has already been purchased (Rosenberg, 1995). Suggestive selling has been used in financial services (Andrews, 1999), retailing (D’Aversa-Williams, 2001) and catalog marketing (Lauderbaugh, 2002). Although Corresponding author.
E-mail address: [email protected] (C. Ebster). 0969-6989/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.jretconser.2005.08.003
the employees delivering scripted purchase suggestions might occasionally resent having to ‘‘push’’ products on their customers, as the suggestions made could come across as insincere or inappropriate (Leidner, 1993), anecdotal evidence suggests that suggestive selling can be a very effective method in increasing sales. In 1987, Martinko and, in 1989 Martinko, White, and Hassell demonstrated that suggestive selling could effectively increase sales. However, since then, little has been published on the effectiveness of suggestive selling in academic consumer behavior literature. As a result, this paper aims to examine the effectiveness of suggestive selling in fast food restaurants. Not only is the general effectiveness of suggestive selling investigated, but its use in conjunction with a variety of products as well as the effectiveness of different suggestion wordings is also examined. Furthermore, the potential influence of descriptive variables (e.g. gender and age of the customer, time of visit to the fast food restaurant, and location of the restaurant) is considered. Finally, given that the origin of this study is Austria and most practitioners’ reports on the effectiveness of this promotional technique originate from the US, it is also intended to assess whether
ARTICLE IN PRESS 170
C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
suggestive selling can effectively be implemented in a cultural context outside the USA.
2. Theoretical background to suggestive selling A conceptual background to suggestive selling can be found in operant psychology, a theoretical approach which has received renewed interest from consumer researchers in recent years (Foxall, 2002). Operant psychology focuses on directly observable behavior and was first introduced to a broader group of marketing researchers by Nord and Peter (1980) under the name of ‘‘behavior modification perspective’’. A basic assumption of operant conditioning is that people learn by producing changes in their environment. A central tenant of operant psychology is the antecedent–behavior–consequence (ABC) model. Antecedent stimuli (A) trigger behavior (B), which is followed by positive or negative consequences (C). These in turn influence the probability that this behavior will recur in the future (Skinner, 1969). According to the ‘‘law of effects’’ (Thorndike, 1911), if a behavior results in positive consequences, it will be repeated more frequently in the future. If followed by negative consequences, the likelihood of recurrence decreases. For example, in a fast food restaurant, antecedent stimuli—such as product displays, flyers, and recommendations from accompanying friends—might trigger customers to order a side dish. The customer’s satisfaction or dissatisfaction with the taste as well as a number of other consumption related factors determine the likelihood that the individual will reorder this side dish in the future. Prompts are a special type of antecedent stimuli, i.e. supplemental stimuli that help to initiate a desired behavior (Touchette and Howard, 1984). The desired response can be prompted in different ways. In a sales situation, gestural, physical, environmental and verbal prompts can be used. For example, to stimulate sales in a fast food restaurant, the salespersons could point to a dessert (gestural prompt) or hold a dessert tray in the customer’s direction (physical prompt). Illuminated boards over the sales counter and displays offering ‘‘specials’’ are examples of environmental prompts frequently used in fast food restaurants. When the staff in fast food restaurants offers customers items related to their original order, such as fries to go with a burger (cross-selling) or larger sizes (upselling), these suggestions can be considered verbal prompts. Verbal prompts were successfully used in social marketing to increase blood donations (Ferrari et al., 1985) and to encourage drivers to wear seatbelts (Engerman et al., 1997). In a services marketing context, verbal prompts were found to improve appointment keeping in a pediatric clinic (Friman et al., 1985).
Furthermore, verbal prompts were shown to increase sales of food and drinks in restaurants (Martinko, 1987; Martinko et al., 1989). Therefore, prompts might also be effective when cross-selling side dishes in a fast food restaurant. This leads us to propose Hypothesis 1: H1. The use of verbal prompts increases sales of side dishes. The specific wording of verbal prompts was found to be of particular importance in their effectiveness (Feeney et al., 1982). From informal discussions with managers and staff of fast food restaurants, we concluded that the effectiveness of prompting can be increased if prompts are delivered in a ‘‘forced choice’’ question, i.e. customers are prompted to order either one product or another. Support for the proposition that forced choice questions might lead to greater compliance with the request also comes from the ‘‘mindlessness principle’’ proposed by Langer et al. (1978). They found that for trivial, non-demanding requests, subjects avoid investing cognitive efforts and rely strongly on general knowledge structures. It is assumed that people are put into a state of mindlessness primarily in routine conversations that have frequently occurred in the past (Langer & Moldoveanu, 2000). Therefore, by wording prompts in a forced choice question format, consumers might feel obliged to choose one of two alternatives, resulting in more orders of the prompted product, as stated in Hypothesis 2: H2. The use of forced-choice verbal prompts is more effective in increasing the sales of side dishes than the use of regular verbal prompts. It seems probable that not only the wording of the prompts, but also the product that the customers are prompted to consider influence the effectiveness of prompting to a greater extent. We hypothesized that prompting would be more successful if the product prompted (i.e. the side dish) has a good fit with the main dish ordered. For example, in Austria, schnitzels (breaded pork/veal cutlets) are a national dish usually served with potato salad or fries. However, in Austria, unlike in the US, sandwiches are considered a light snack and are not usually served with a side dish. Accordingly, Hypothesis 3 states: H3. Prompting side dishes is more effective when consumers see a fit between the main dish and the side dish. Prompting is assumed to be a behavioral method used to initiate a behavior not previously shown (Kazdin, 1994). Therefore, it might be more effective to prompt customers to order a side dish with their main dish, if the
ARTICLE IN PRESS C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
main dish is a new addition to the menu rather than a dish traditionally ordered in a specific (type of) restaurant. The idea that prompting might be more effective when used in conjunction with dishes that customers are unlikely to have received previous prompting for, is supported by correspondent-inference theory (Jones and McGillis, 1976). This theory, which has been used by consumer researchers to explain some of the effects of price promotions (Lichtenstein et al., 1991), states that consumers are more likely to process and elaborate information when it is unexpected or unusual. When an event is unexpected, customers can no longer assimilate it into their existing knowledge structures, which may lead them to consciously examine their previous assumptions (Fo¨rsterling, 2001). This might happen, for example, when a customer orders a newly added item, such as a vegetarian dish for the first time, and is consequently prompted for the first time to order a side dish with this meal. According to correspondent-inference theory, behavioral observations are unexpected when the information is inconsistent with previous information or when it is distinct from other current information (Jones and McGillis, 1976). Consequently, restaurant patrons might respond more positively to suggestive selling when it is unlikely that they have been previously prompted to order a side dish with a specific main dish, or when they order a main dish not usually offered in a specific restaurant category. Accordingly, Hypothesis 4 states: H4. Prompting side dishes is more effective in increasing sales of side dishes when the main dishes are less familiar to customers in a restaurant. Further support for this hypothesis comes from the concept of perceived risk (Bauer, 1960), a customer’s subjective anticipation of loss from a product that does not provide all expected benefits (Roselius, 1971; Sweeney et al., 1999). Ordering an unfamiliar main dish or a main dish one has not tried in a restaurant might be somewhat risky for a restaurant patron. Ordering a side dish known to the customer together with the unfamiliar main dish might lower perceived risk as the customer is at least familiar with the taste and quality of the side dish, thereby increasing the likelihood of purchase upon exposure to a verbal prompt.
3. Method 3.1. Research setting In order to test the above hypotheses, an empirical research project was undertaken. We decided to use a causal design, and observation as the data collection method. A field experiment was conducted in an
171
Austrian fast food restaurant chain, specializing in a variety of schnitzels, but also serving sandwiches and chicken nuggets. Two weeks prior to the experiment, vegetarian and fish dishes, two product categories not offered by most Austrian fast food restaurants, were added to the menu. Data were collected over a period of 2 weeks in two branches of the chain. One was located in the food court of a shopping mall in a large city with a population of approximately 1,750,000, the other on the main street of a small town with approximately 10,000 inhabitants. Prior to the experiment, suggestive selling had not been used by the restaurant chain. 3.2. Design and procedure Before starting the experiment, the sales clerks of the two participating restaurants were trained in delivering the prompts to the customers. They were informed of the general nature of the experiment, but were blind to the specific hypotheses being tested. An after-only with control group design was chosen. Participants were assigned to one of four experimental situations based on the sequence of their arrival at the counter. Successive groups of ten customers ordering one of the main dishes offered (schnitzel, fish, vegetarian dishes, chicken nuggets, sandwiches) were assigned to one experimental condition. After having served the tenth customer, the next experimental condition came into effect. In experimental condition 1 (EG 1), customers were prompted to order potato salad with their main course. The wording of the suggestion was: ‘‘Would you like potato salad with that?’’ In experimental condition 2 (EG 2), they were prompted to order fries. Customers were asked: ‘‘Would you like fries with that?’’ In condition 3 (EG 3), a forced-choice question format was used to prompt the ordering of a side dish: ‘‘Would you like potato salad with that or would you prefer fries?’’ In condition 4, the control group (CG), no prompts were used at all. In order to determine the effectiveness of prompting by mere comparison of the experimental and control groups, suggestions to order a side dish were only used when patrons did not request it themselves, i.e. not all customers within the experimental groups were exposed to prompting. Data were collected at lunch time (11:30 a.m.–2:00 p.m.) and at dinner time (6:00 p.m.–10:00 p.m.). In both restaurants, there was only one cash desk, where customers ordered and paid for their food. An unobtrusive experimenter stood to one side, using differently colored cards to signal which experimental treatment the restaurant employee should adopt. The cards were attached to a rolodex-like device (visible only to the employee) and flipped to indicate a change in the experimental condition after ten customers. The experimenter recorded the main and side dishes ordered,
ARTICLE IN PRESS 172
C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
as well as the time of the sales interaction (lunch or dinner time) on a standardized observational form. The customer’s gender was also recorded and judgment was used to classify customers as children (below the age of 16) or adults. The customers were only observed but not interviewed in order to ensure an unobtrusive purchase situation and to exclude socially desirable response behavior.
4. Results 4.1. Effectiveness of verbal prompts—H1 The four groups were balanced with respect to location, time and size (each group contained 540 observations). A total of 2160 sales transactions were recorded in the course of the experiment, of which 1589 customers (74%) ordered side dishes with their main courses. The greatest percentage of customers ordering side dishes (79%) was in experimental group 1 (potato salad prompt), followed by 78% in experimental group 3 (potato salad and fries prompt) and 77% in experimental group 2 (fries prompt) (see Table 1). To investigate Hypothesis 1, the data from column 2 in Table 1 were used (i.e. experimental groups were pooled into a single category EG). The w2-test rejected independence between the experimental variable and the number of ‘‘side dishes ordered’’ (^w2 ¼ 59:1, 1 degree-offreedom, which corresponds to a p-level less than 0.01). This result is in line with intuitive interpretation of the data and clearly supports H1: prompted customers order side dishes more often, i.e. sales increased by a magnitude of about 17 percentage points. 4.2. Effectiveness of different prompting conditions—H2 Hypothesis 2 was analyzed by concentrating on the results of the three different experimental conditions (data from column 3, rows 3 to 5 in Table 1). The w2-test did not reject independence between the experimental variable and the number of ‘‘side dishes ordered’’ (^w2 ¼ 0:9, 2 degrees of freedom, which corresponds to a p-level greater than 0.1). This result is consistent with visual inspection of the data. Thus, the specific format of a verbal prompt, open or forced-choice question does
not appear to influence their effectiveness. Therefore, customers belonging to all three experimental groups were pooled into a single category called ‘experimental group’ (EG) for subsequent analyses. 4.3. Further descriptive analysis of the data In the previous section, it has already been argued that, besides prompting, there are a number of other potential influences on the probability of ordering a side dish. Preliminary examination of the situation at hand established ‘type of main dish ordered’ and ‘age of customer’ to be of relevance, the other variables being of minor (‘location of the restaurant’) or no importance (‘gender’, ‘time’). Looking at Fig. 1, four observations are apparent. (i) There is a consistent effect of the treatment variable. The percentages of side dishes ordered in the experimental group exceed the corresponding numbers for the control group in all cases. (ii) The type of main dish chosen matters. The five different options vary with respect to the frequency of side dishes ordered. There are two extreme cases. On the one hand, it is very popular to eat schnitzel with a side dish; while quite the opposite situation is evident for sandwiches, which seem to be preferred without accompaniment. Focusing on the results for the control group only, approximately the same number of patrons order side dishes with fish (69%) as with chicken nuggets (65%). (iii) Besides these disparities in magnitude, there is an impact on the effectiveness of prompting depending on the main dish chosen. This can be verified by looking at the differences between the percentages of EG and CG (these numbers are shown in Fig. 1). With the vegetarian dish, for example, about a 31-percentage point difference is found, whereas with chicken nuggets there is a 6-percentage point difference. Consequently, if analyzing the odds of ordering a side dish (versus not ordering a side dish) and comparing the odds for the two categories of the treatment variable (e.g. for the vegetarian dish), a score of 3.6, i.e. (66/(10066))/(35/(10035)) results. In both cases prompting is found to be less effective for chicken nuggets and sandwiches.
Table 1
CG: no prompt EG: prompt
Number/percentages of respondents ordering side dishes
Group size
329/61% 1260/78%
540 540 540 540 2160
1589/74%
427/79% 414/77% 419/78%
EG 1: potato salad prompt EG 2: fries prompt EG 3: potato salad and fries prompt
ARTICLE IN PRESS C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
173
Fig. 1. Differences in percentages between experimental group and control group.
(iv) The frequencies of side dishes ordered vary by age. Adults consume side dishes more often than children do. 4.4. Logistic regression analysis In Sections 4.1 and 4.2, only two variables at a time were studied by means of cross-tabulations. Section 4.3 has shown that other influences (e.g. age, main dish chosen) should be considered as well, and therefore, given the categorical character of the data, multiway frequency analysis was applied. Since the ‘‘number of side dishes’’ ordered is considered a dependent variable, logistic regression offers a convenient way to analyze the data. Therefore, a log-linear model is postulated to describe how ‘‘prompting’’, ‘‘age’’ and ‘‘main dish chosen’’ influence the probability of ordering a side dish. Because of observation (iii) in Section 4.3, the second-order effect /experimental stimulusmain dishS was additionally included. In mathematical terms, the model can be written as follows: ! Sd^ jkl ln 1 S d^ jkl ¼ const þ lEX j þ lAk þ lMDl þ lEX j nMDl þ ujkl with S d^jkl
estimated probability (percentage) that a side dish is ordered for cell (j, k, l);
effect of the experimental stimulus results are given in a relative sense, i.e. with respect to the reference category control group (lEX CG ¼ 0); je{EG, CG}; lA k effect of age results are given in a relative sense, i.e. with respect to the reference category child (lAchild ¼ 0); ke {adult, child}; lMDl effect of the main dish chosen results are given in a relative sense, i.e. with respect to the reference category sandwiches (lMDsandwiches ¼ 0); le {schnitzel, fish, vegetarian dish, chicken nuggets, sandwiches}; lEX j MDl second-order effect of experimental stimulus by main dish chosen; ujkl error term.
lEX j
Viewed as a special kind of multiway frequency analysis, our data is a 2225 table, with 2160 observations in total, distributed among the 40 cells. Furthermore, as there are only two observed cell frequencies with less than 5, the basic requirements for running a logistic regression are fulfilled. The results are presented in Table 2. By looking at the parameter estimates, significant influences for all independent variables are found. Since the parameter estimates describe the linear effects of the predictors on the log of the odds ratio of the outcome category, interpretation is more intuitive in terms of the
ARTICLE IN PRESS 174
C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
Table 2 Logistic regression: probability of ordering a side disha Independent variables
Parameter estimates 1.24 0.52 0.64 2.63 1.95
Odds ratio
Constant Experimental groupb Adultc Schnitzeld Fishd Vegetarian dishd Chicken nuggetsd Schnitzel experimental group Fish experimental group Vegetarian dish experimental group Chicken nuggets experimental group
0.49 2.11 1.12 0.98 0.77 0.33
1.68 1.90 13.80 7.04 1.64 8.21 3.06 2.68 2.17 0.72
Goodness-of-fit LR-test against ‘constant-only model’ LR-test against ‘full model’
w^ 2 ¼ 856:79 2 G^ ¼ 5:01
df ¼ 10 df ¼ 9
hit rate ¼ 84.2% (Cmax ¼ 73.6%e) r2 ¼ 0:34
N ¼ 2160 (Cpro ¼ 61.1%f)
‘Perfect model’ Pseudo-R2 (McFadden, 1974) Significant at the 10% level. Significant at the 5% level. Significant at the 1% level. a
Reference category: no side dish ordered. Reference category: control group. c Reference category: child. d Reference category: sandwiches. e Benchmark maximum chance criterion. f Benchmark proportional chance criterion. b
coefficients’ odds ratio (i.e. expðl^ Þ). For example, a customer choosing fish as a main dish is seven times more likely to order a side dish than a person having sandwiches. It can be noted that ‘‘main dish chosen’’ is the most influential regressor. Moreover, adults consume side dishes almost twice as often as children. The reasons for this are numerous. For example, children do not eat as much as adults and, therefore, are satiated with less food and do not need side dishes to satisfy their appetite. In addition, children probably have more restrictions on money at their disposal and, therefore, cannot afford to buy a side dish (even if they wanted to). When accounting for other effects, prompting is nevertheless found to have a significant influence, i.e. the odds of ordering a side dish are 1.68:1 in this case (whereas a rough estimate of the odds based on the data in Table 1 would be 2.27:1, i.e. (0.78/0.22)/(0.61/.039)). This result is in line with the approximation of the odds of ordering a side dish when belonging to the experimental group and ordering the vegetarian dish. In comment (iii) of Section 4.3 a preliminary estimate of 3.6 was derived which has to be compared with the estimate of 2.17 in Table 2. Simultaneous consideration of several effects reduces the magnitude of individual effects when looked upon in isolation.
Goodness-of-fit is also satisfactory. Statistical testing rejects the assumption that a constant-only model fits as well as the proposed one, but does not reject the full (i.e. saturated) model. Classification based upon the model fails only in about 16% of the cases (due to limited data, it was not possible to divide the data into an estimation and a hold-out sample to provide a more stringent calculation of the hit rate). A detailed analysis of the standardized residuals shows that all of them are smaller than 1.1 (in absolute value), and therefore there are no outliers in the data. Finally, pseudo R2 (McFadden, 1974) is also acceptable, enabling us to conclude that logistic regression provides results which are face valid as well as statistically sound. In accordance with preliminary results, the proposed model outperforms alternative formulations (with other independent variables such as ‘‘gender’’, ‘‘location of restaurants’’ or ‘‘time’’). 4.5. Investigation of H3 and H4 With respect to Hypotheses 3 and 4, it is interesting to observe the estimates of the interaction variable, e.g. prompting a patron who orders a schnitzel is three times more effective than if he were to ask for sandwiches (or
ARTICLE IN PRESS C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
chicken nuggets). Bearing in mind that schnitzels are usually served with a potato-based side dish in Austria, the significance of this parameter supports Hypothesis 3. The second-order effect is also significant for fish and the vegetarian dishes, although the odds ratios are slightly lower. In view of the rather similar percentages of side dishes ordered within the control group for fish and chicken nuggets (c.f. remark (ii) in Section 4.3 above), the increased effectiveness of prompting with fish dishes must be due to some external influence not considered until now. We attribute this to the fact that fish dishes have only been added to the menu recently, but concede that causality (in the strictest sense) has not, as yet, been established. Similarly, when comparing the vegetarian dish and sandwiches, the same pattern is identified, however, to a lesser extent. Subsequently, results are in line with Hypothesis 4.
5. Discussion This study examined the effectiveness of suggestive selling using verbal prompts. It has been shown that verbal prompts can lead to significant increases (16–18 percentage points) in sales of side dishes in fast food restaurants. This finding is consistent with the results of studies conducted in social marketing. Moreover, the hypothesis based on correspondent-inference theory, whereby prompts are more effective in increasing sales of side dishes when used in conjunction with behavior not previously performed, i.e. ordering side dishes with main dishes atypical for the restaurant, is supported by the results. However, the wording of the prompts did not appear to influence their effectiveness, and in particular the forced-choice prompt was not found to be more effective than regular verbal prompts. A possible explanation for this might be that both side dishes prompted were potato-based food items. While the results suggest that both fries and potato salad are highly popular with the restaurants’ patrons, it seems unlikely that the particular phrase used to suggest a side dish might have led customers who dislike potato-based dishes to overcome their dislike. 5.1. Limitations and areas for future research While this field experiment has demonstrated that verbal prompts are effective in fast food restaurants, caution should be exercised in generalizing these findings to other settings. Furthermore, correspondentinference theory can only partially explain the effectiveness of prompts. In the course of this study, it was not possible to conclude how effective prompts should be worded, a relevant issue for consumer researchers and practitioners alike. Further studies to investigate whether the effectiveness of suggestive selling can be
175
extended to related industries, and which factors, apart from the typicality of products, are influential, are warranted. An important factor in the effectiveness of suggestive selling might be whether a functional or hedonic product is being prompted. This distinction has been shown to influence price sensitivity (Wakefield and Inman, 2003) and could also extend to sales promotion effectiveness. Furthermore, further research could examine the role of social influence on the effectiveness of prompts. While only single orders (i.e. customers ordering one meal) were included in the present study, the effectiveness of prompts when multiple orders are placed and when customers order as part of a group, should be examined in future studies. Finally, it might be worth investigating the long-term effects of verbal prompting, and its impact on customer satisfaction and store loyalty. 5.2. Managerial implications From a managerial standpoint, it should be noted that verbal prompts could be a promising and costefficient sales promotion tool. Nevertheless, it should not be forgotten that prompting could lead to resistance from both employees and customers. Therefore, special care should be taken to overcome this reactance. To mitigate employees’ reactance to prompting, clear rules as to when sales should be prompted should be given, while at the same time allowing staff to use discretion when not to prompt (e.g. in the case of regular customers, fellow employees or children). In an empirical study, Johnson and Masotti (1990) found that behavioral interventions such as feedback, goal setting and positive reinforcement by management can increase appropriate suggested selling by employees. To minimize customers’ annoyance when prompted for additional purchases, prompting should only be encouraged with items complementing the purchase and prompts should be delivered in a courteous, non-demanding way. In conclusion, prompts can only achieve their full potential, if they are integrated in overall human resource and sales training strategy. Nevertheless, they can be a very valuable marketing tool. In fact, as a result of the obvious effectiveness of verbal prompting and its efficiency compared to alternative sales promotion instruments, such as price promotions, the fast food company involved in this experiment has been using suggestive selling ever since.
Acknowledgements The authors wish to thank two anonymous reviewers for their valuable comments on an earlier version of this article.
ARTICLE IN PRESS 176
C. Ebster et al. / Journal of Retailing and Consumer Services 13 (2006) 169–176
References Andrews, K.J., 1999. Extending upselling and cross-selling efforts. Target Marketing 22, 36–40. Bauer, R.A., 1960. Consumer behavior as risk taking. In: Hancock, R.S. (Ed.), Dynamic Marketing for a Changing World: Proceedings of the 43rd Conference of the American Marketing Association, pp. 389–398. D’Aversa-Williams, T., 2001. Merchandising+suggestive selling ¼ accessory sales. Sporting Goods Business 34, 44. Engerman, J.A., Austin, J., Bailey, J.S., 1997. Prompting patron safety belt use at a supermarket. Journal of Applied Behavior Analysis 30, 577–579. Feeney, E.J., Staelin, J.R., O’Brien, R.M., Dickinson, A.M., 1982. Increasing sales performance among airline reservation personnel. In: O’Brien, R.M., Dickinson, A.M., Rosow, M. (Eds.), Industrial Behavior Modification: A Management Handbook. Pergamon Press, New York, pp. 141–158. Ferrari, J.R., Barone, R.C., Jason, L.A., Rose, T., 1985. The use of incentives to increase blood donations. Journal of Social Psychology 125, 791–793. Fo¨rsterling, F., 2001. Attribution: An Introduction to Theories, Research, and Applications. Taylor & Francis, Philadelphia, PA. Foxall, G.R. (Ed.), 2002. Consumer Behaviour Analysis: Critical Perspectives on Business and Management. Routledge, London. Friman, P.C., Finney, J.W., Rapoff, M.A., Christophersen, E.R., 1985. Improving pediatric appointment keeping with reminders and reduced response requirement. Journal of Applied Behavior Analysis 18, 315–321. Johnson, C.M., Masotti, R.M., 1990. Suggestive selling by waitstaff in a family style restaurant. Journal of Organizational Behavior Mangement 11, 35–54. Jones, E.E., McGillis, D., 1976. Correspondent inference and the attribution cube: a comparative reappraisal. In: Harvey, J.H., Ickes, W.J., Kidd, R.F. (Eds.), New Directions in Attribution Research, vol. 1. Erlbaum, New York, pp. 389–419. Kazdin, A.E., 1994. Behavior Modification in Applied Settings, fifth ed. Brooks/Cole Publishing, Pacific Grove, CA. Langer, E.J., Moldoveanu, M., 2000. Mindfulness theory and the future. Journal of Social Issues 56, 129–139.
Langer, E.J., Blank, A., Chanowitz, B., 1978. The mindlessness of ostensibly thoughtful action: The role of ‘‘placebic’’ information in interpersonal interaction. Journal of Personality and Social Psychology 36, 635–642. Lauderbaugh, J.J., 2002. Embracing the upsell: Increase sales by shifting your phone reps’ mindset from service to sales. Catalog Age 19 (6), 49–50. Leidner, R., 1993. Fast Food, Fast Talk: Service Work and the Routinization of Everyday Life. University of California Press, Berkeley, CA. Lichtenstein, D.R., Burton, S., Karson, E.J., 1991. The effect of semantic cues on consumer perception of reference price ads. Journal of Consumer Research 18, 380–391. Martinko, M.J., 1987. An O. B. Mod. analysis of consumer behavior. Journal of Organizational Behavior Management 8, 19–43. Martinko, M.J., White, J.D., Hassell, B., 1989. An operant analysis of prompting in a sales environment. Journal of Organizational Behavior Management 10, 93–107. McFadden, D., 1974. Conditional logit analysis of qualitative choice behavior. In: Zarembka, P. (Ed.), Frontiers in Econometrics. Academic Press, New York, pp. 105–142. Nord, W.R., Peter, J.P., 1980. A behavior modification perspective on marketing. Journal of Marketing 44, 36–47. Roselius, T., 1971. Consumer ranking of risk reduction methods. Journal of Marketing 35, 56–61. Rosenberg, J., 1995. Dictionary of Retailing and Merchandising. Wiley, New York. Skinner, B.F., 1969. Contingencies of Reinforcement: a Theoretical Analysis. Prentice-Hall, Englewood Cliffs, NJ. Sweeney, J.C., Soutar, G.N., Johnson, LW., 1999. The role of perceived risk in the quality-value relationship: a study in a retail environment. Journal of Retailing 75, 77–105. Thorndike, E.L., 1911. Animal Intelligence. Macmillan, New York. Touchette, P.E., Howard, J.S., 1984. The effects of verbal performance descriptions on nonverbal operant responding. Journal of the Experimental Analysis of Behavior 54, 273–291. Wakefield, K.L., Inman, J.J., 2003. Situational price sensitivity: the role of consumption occasion, social context and income. Journal of Retailing 79, 199–212.