Employee Recognition and Performance - A Field Experiment

Employee Recognition and Performance - A Field Experiment Christiane Bradler, Robert Dur, Susanne Neckermann, Arjan Non Preliminary draft, October 2011 Abstract Recognition for a job well done is commonly considered as an important management tool for motivating employees. Existing empirical studies show strong positive correlations between the provision of recognition and employee performance, but often fail to establish causality. This paper contributes to filling this gap by conducting a field experiment in a natural working environment. We hired more than 400 students for a three-hour job. Participants worked individually on a data entry task in groups of eight. We randomized the unannounced provision of recognition (in the form of handing out a thank-you card) after two hours of work. We find that the provision of recognition to all workers in a group increases subsequent performance only weakly. In contrast, scarce recognition that is only provided to the best performers in a group raises subsequent perfomance substantially. Remarkably, workers who did not receive recognition are responsible for this performance increase. These results are consistent with workers having preferences for conformity and being reciprocal at the same time. All effects vanish completely when the reward is announced. JEL Classification: C93, M52 Key words: employee motivation, recognition, reciprocity, conformity, field experiment ZEW Centre for European Economic Research Mannheim Erasmus University Rotterdam ZEW Centre for European Economic Research and University of Mannheim University of Maastricht 1

1 Introduction Recent years have seen a surge in popular business books on the importance of recognition for employee motivation. A prominent book in this field is Bob Nelson s 1001 Ways to Reward Employees. He starts his book by stating that a number of surveys confirm what almost every employee already knows: that recognition for a job well done is the top motivator of employee performance. 1 Other questionnaire studies reveal similar views among practitioners, see among others Kovach (1995) and Wiley (1997). The academic literature provides surprisingly little sound evidence for the effects of employee recognition on work performance. Most existing studies rely on correlations between the provision of recognition and employee performance (e.g. Rhoades and Eisenberger 2002, Cropanzano and Mitchell 2005, and Wagner and Harter, 2006). recognize, correlation does not prove causation. However, as these studies For instance, and quite naturally, good performance also causes recognition, making it difficult to detect a possible causal effect of recognition on performance using observational data. (Quasi-)experimental studies improve on this by exploiting random variation in the type and/or amount of recognition provided to employees (Neckermann et al., 2010). Experimental studies are very scarce, though, particularly those conducted in a natural work environment and with a reasonable sample size. 2 This paper contributes to fill this important gap in the literature by conducting a large-scale field experiment in a natural working environment. Over the course of November 2010 to May 2011, we hired more than 400 people (mainly students) for a three-hour data entry job. We created a work environment where eight workers shared the same room, but worked individually. Workers were paid a flat wage of 25 Euro and were not aware that they took part in an experiment. A random sample of workers received recognition after two hours of work. Recognition consisted of a thank-you card, personally signed by the head of the research institute and handed out by a research assistant. Thus, provision of recognition did not involve any material reward but clearly showed the management s appreciation for workers effort. Importantly (and most naturally), 1 He continues with yet most managers do not understand or use the potential power of recognition and rewards [...] while money is important to employees, research shows that what motivates them really to perform [...] is the thoughtful, personal kind of recognition that signifies true appreciation for a job well done. 2 An early lab experiment is by Deci (1971), who showed that provision of praise increases students willingness to work on a puzzle. Stajkovic and Luthans (2003) give an overview of field-experimental studies on the effect of social recognition on employees performance. These studies typically randomize over a handful of plants and do not correct standard errors for clustering at the plant level. Other field studies have experimentally examined the effects of recognition on employee absenteeism (Markham et al., 2002) and on parents willingness to volunteer for their kids soccer club (Fisher and Ackerman, 1998). Most recently, Neckermann et al. (2010) analyze firm-level data to compare the behavior of employees receiving an award with observationally similar employees not receiving an award. They find that award recipients significantly increase performance as compared to non-recipients. 1

in most of the treatments possible provision of recognition was not announced at the start of the three-hour working period. Moreover, from the way the thank-you card was presented, workers could deduct that no further recognition would be provided in the remainder of the working period. A key feature of our experiment is that we vary the scarcity of recognition over different treatments. In one treatment, all workers in a work group receive the thank-you card. In other treatments, the thank-you card is given only to the best performer or to the best three performers of a work group, and this is publicly announced when handing out the thank-you cards. Our main focus is on how the provision of the thank-you card affects subsequent performance of workers. We argue that three behavioral mechanisms may be operational: signaling by the employer, reciprocity of employees, and conformity preferences of employees. As we shall see, our results are consistent with employees having preferences for conformity and being reciprocal at the same time. The paper proceeds as follows. In the next section, we draw on existing behavioral theories to develop hypotheses on the effects of different forms of recognition. Next, we describe the experimental set-up in detail in Section 3. Section 4 lays out the empirical strategy and presents the results of our experiments. Section 5 concludes. 2 Theory Why might the provision of a thank-you-card that was not announced affect subsequent effort of workers? And does it matter whether all workers or only the best performing workers in a session receive a thank-you card? We can think of three plausible behavioral mechanisms through which a thank-you card may affect subsequent effort. First, workers may consider the thank-you card as a gift from the employer and feel inclined to reciprocate. A natural way to reciprocate is to increase effort in the remainder of the session. Following the seminal paper by Akerlof (1982) and the influential experimental work by Fehr et al. (1993), reciprocity has become a firmly established concept in economics. Most studies in economics have focused on wages as the employer s means of exchange in reciprocal relationships with workers. An exception is Kube et al. (2011) who show that non-pecuniary gifts increase subsequent work effort. Other social sciences have also considered socio-emotional gifts that address social and esteem needs (and are often symbolic and particularistic) (Cropanzano and Mitchell, 2005, p. 881). The thank-you card which is central to our treatments, clearly falls into this latter category. In treatments where only a subset of workers receive a thank-you card, we only expect recipients to respond. Moreover, scarcity may affect the perceived value of the card, implying a stronger response of recipients when the 2

number of recipients decreases. A second reason for why the thank-you card may affect effort is that the card provides a signal to the workers about the employer s type. For instance, the thank-you card may signal the employer s kindness or care for the workers, which may in turn make workers care more for the employer and hence increase their effort (Levine, 1998; Dur, 2009). Alternatively, the thank you card may affect workers beliefs about how important their effort is to the employer. According to these signaling theories, the thank-you card should affect effort of recipients and non-recipients identically as all workers receive the signal (the cards are handed out in public). However, the strength of the response may differ between treatments. In particular, providing just a single card may be seen as a weaker signal of kindness or care for output than providing all workers with a thank-you card. Third and last, in the treatments where only the best-performing workers receive a thank-you card, preferences for conformity may give rise to behavioral responses. Recipients in these treatments learn that their performance belongs to the top within their group. Likewise, non-recipients learn that they belong to the lower ends of the performance distribution. workers have a preference for conformity (as in Bernheim, 1994, and Sliwka, 2007), we expect non-recipients to increase effort while recipients reduce effort. The effect on non-recipients should be less pronounced when the thank-you card is provided to very few workers, as less information is provided about one s standing. Thus, we expect smaller effects for non-recipients in the treatment where only a single thank-you-card is provided as compared to the treatment where the three best-performing workers receive a thank-you card. Conversely, recipients of the card should respond more strongly when fewer thank-you cards are provided. If Lastly, conformity preferences predict no treatment effect in the treatment where all workers are provided with a thank-you card, as no information about one s relative performance is revealed. 3 Table 1 summarizes our theoretical predictions. 3 The effect of relative performance feedback on performance has recently been studied in a variety of contexts, ranging from student test scores (Bandiera and Larcinese, 2009; Azmat and Iriberri, 2010; Tran and Zeckhauser, 2011), contributions to an online community (Chen et al., 2010), real-effort in the lab (Charness et al., 2010; Freeman and Gelber, 2010; Kuhnen and Tymula, 2011), to workers performance in a real working environment (Falk, 2006; Delfgaauw, 2009; Blanes i Vidal, 2011; Barankay, 2011a, 2011b). With the noteworthy exception of Barankay (2011a,2011b), all of these papers find that relative performance feedback has on average a positive effect on performance. A subset of these papers also look at where in the performance distribution people are most responsive to feedback; results tend to be mixed in this respect. 3

Figure 1: Theoretical Predictions We also ran a treatment where the provision of thank-you cards was announced as in Kosfeld and Neckermann (2011). Specifically, in this treatment it was announced at the beginning of the work session that the three best-performing workers in the first two hours of the session would receive a thank-you-card after two hours of work. If workers value the card, this announcement introduces tournament incentives in the first two hours of the session and thus should increase performance. The three mechanisms discussed above may also be operative. Therefore, recipients may reciprocate receiving the gift in the second half of the session; workers may consider the thank-you card as a signal of the employer s kindness or care for output, increasing performance in both the first and second half of the experiment; and, in the second half of the experiment, workers may adjust effort so as to better conform to what is common in their group. However, one could also argue that conditional rewards do not cause a reciprocal action. 3 Design and Implementation 3.1 Background of Study In order to test these hypotheses, we conducted a natural field experiment (according to the taxanomy laid out in Harrison and List (2004). 4 This means that we observed participants in a natural labor environment and that subjects were not aware of the fact that they were part of an experiment. 5 In the name of a German research institute the Centre for European 4 In addition to the treatments reported in this paper, we conducted three additional treatments investigating the motivational production function. Results on these treatments are reported in Bradler and Neckermann (2011). 5 The experiment has been conducted within the ethical guidelines of our home institutions. 4

Economic Research (ZEW) we hired students for a one-time data entry job between November 2010 and May 2011. The institute had just received several hundreds of surveys that could not be processed automatically, which made manual entry into a database necessary. For this job, we hired students from different universities in and around Mannheim via student job centers, flyers, and notes on bulletin boards. The announcement informed subjects that the research center needed short-term student helpers for a three-hour data entry job and that subjects would earn 25 Euro fixed wage in total. 6. Students could sign up for the job online and were subsequently contacted via phone to arrange date and time. We minimized reputation concerns as much as possible by informing participants that the job was one-time, a second participation was not possible due to taxed-based reasons 7, and that no permanently employed research assistants were needed at the moment for either this or other projects. We invited subjects in groups of eight. Sessions took place in the morning, at noon, and in the afternoon. 8 We implemented recognition by handing out thank-you cards (see Figure 2 in the Appendix) to subjects. Depending on the treatment, these thank-you cards were either announced or came as a suprise after two hours of work; they were given to all participants or only to the best three or the best one in the work session. 3.2 Implementation Upon arrival, participants were seated in front of a workstation. The workspaces were arranged in a U-shape and with sufficient space between individuals to ensure that subjects felt unobserved. Then, all formalities (privacy policy, wage agreement) were taken care of and the 25 Euro were paid in advance. This conveyed the fact that payment was made independent of the following work performance. Subsequently, the participants received a short introduction to their employer (ZEW) and to the project the questionnaires were to be filled for. questionnaires were part of an evaluation project in the educational context and involved surveys from several hundred students on their school and career preferences. Additionally, a short briefing was given on how to file the answers from the questionnaires into the database. The data were filed via a web interface; hence, access to the internet was visible and possible at any time. The interface was set up like an online version of the surveys that the participants had in front of them in paper format. 9 The On the screen subjects needed to transfer the answers 6 The fixed wage was chosen according to hourly wage rates of student research assistants 7 In case of a second participation, partcipants would exceed the threshold of earnings beyond which tax-based informations needs to be collected. This would cause substantial administrative expenses for fiscal reporting 8 The field experiment was carried out in two locations, at the Centre of Economic Research in Mannheim and at the Ruprecht-Karls University of Heidelberg. In the regressions we control for time of day as well as for day of week and for location effects, but these do not affect the results. All sessions were conducted by the same research assistant. 9 For screen exemplary see Figure 3 in the Appendix. 5

the participants of the questionnaire study had marked in each of the multiple choice questions. For a few questions information from free text fields of the survey had to be entered. This was among others one main reason why the decision was made to enter surveys by hand. The questionnaires were stacked in a high, non-transparent box in front of the participants, with a second identical box next to it to deposit the completed ones. This prevented the participants from comparing their work with each other. The research assistant then left the room, informing participants that she was working outside and was available for queries at any time and that subjects could take breaks whenever necessary. These measures (individual breaks, payment in advance, internet access, absence of supervisor) were taken to give participants substantial leeway in how much time they spend on filling the questionnaires. Furthermore, a collective break was avoided to minimize possible group effects and communication between participants. The task was exhausting and monotonous, and we do not assume that there was much intrinsic motivation involved in completing the task. In fact, participants commented that the filling was very monotonous and boring. Eight participants were assigned to each working session. However, the average number of participants per session was 7.15 (s.d. = 0.89) due to participants who were invited but did not show up. 10 The timeline was as follows: the introduction lasted for about 20 minutes on average. Then, subjects worked on the task for roughly 100 minutes. 11 We refer to this first phase as working period 1. Subsequent to working period 1 (i.e. two hours after participants official start of work), the research assistant entered the room and told subjects that the IT-department of the institute had just confirmed that the data was submitted correctly from each computer to the central data base. 12 As part of this interruption, the intervention depending on the treatment followed. Subsequently, subjects worked for approximately one additional hour which we refer to as working period 2. 13 Working period 1 was longer than working period 2 to allow for variation in introductory period and for learning. After the second working period, feedback forms were handed out, which asked for improvement suggestions and comments on how we handled the short-term employment. 10 Detailed statistics on the number of participants per session and treatment can be found in Table 1 in the Appendix. 11 The standard deviation of the introductory period is 5 minutes (Min. = 9.25 min, Max. = 26.3). Differences in length are due to delays in arrivals of participants or different amount of questions which were raised during the introduction. The standard deviation of the duration of working period 1 is 6.4 min (Min. = 85.7 and Max. = 115.3). Differences in the length of working periods are due to delays in the introduction period. 12 We chose this wording to ensure that in control as well as in the treatment sessions, subjects were aware of the fact that we could link data entered to the respective work station. This way, the perceived degree of monitoring was held constant across sessions as much as possible. 13 The mean of working period 2 is 52,8 min with a standard deviation of 3.75 min (Min.: 40 and Max.: 55). We account for differences in the length of working periods in the statistical analysis by using productivity per minute of working time as the dependent variable. 6

3.3 Treatments We implemented the following five treatments in the study. The different scripts can be found in the Appendix. In all treatments including the control treatment, the research assistant informed subjects that the data were transmitted correctly from all computers to our central server and told them that everything worked as planned. Nothing else happened in the Control group so that we can measure the development of productivity without rewards (learning, fatigue). In treatments involving thank-you cards, she continued that the research team together with the president of the institute had created thank-you cards for all participants of the data entry job as a symbol for the institute s thankfulness and appreciation of the participants support in entering the data. Therefore, the head of the institute, president Professor Franz, had personally signed each card. This allowed us to give a signal of appreciation, which is as salient as possible in such a short-time employment. In the treatment Thank-you card for all (TC All), the research assistant then handed a card to each participant. This treatment allows us to measure the response to a general appreciation and recognition. In the treatment Thank-you card for the best 3 (TC Best3) subjects were informed that the research assistant only had three cards available and spontaneously decided to hand these out to those three persons who had performed best up until then. 14 The scarcity of cards was explained by the fact that the president had not had enough time to sign a card for each participant of this short-term employment. This also ensured that participants did not expect additional cards at the very end of the employment period. As there were fewer than eight students in some sessions, we adjusted the number of cards in accordance to the actual group size to keep the percentage of rewarded subjects comparable. 15 TC Best3 adds scarcity and, hence, status and feedback to general recognition. The treatment Thank-you card for the best 1 (TC Best1) was identical to TC Best3 apart from the fact that there was only one recipient of a thank-you card. Finally, in the treatment Thank-you card for the best 3 announced (TC Best3 announced), we announced at the beginning of working period 1 that thank-you cards would be handed out later on for the three participants who would have performed best up to this point of time. Subjects were informed that rewards would be handed out during an IT check after roughly two hours. We showed the card to the subjects in advance to ensure common knowledge about what the card looked like and to ensure that subjects understood that there was no material value to the reward. This treatment checks for incentive effects and for 14 We measured performance in terms of the number of finished questionnaires in the first working period. Subjects were told that IT provided logins to the research assistant of the three persons that had performed best. The wording was chosen in order to convey the notion that the research assistant could not perfectly monitor everyone s performance. 15 For a group size of 7-8 persons we assigned three TCs, and for a group size of 5-6 persons we assigned two TCs. Obviously, the percentage of rewarded subjects is not kept constant by this variation. We control for group size in all regressions but this does not affect the results. 7

whether ex-post effects depend on the rewards being announced or spontaneous. 16 4 Results We regress the productivity in working period 2 on the treatment dummies and different control variables for baseline productivity in working period 1, demographics such as gender and field of study, time of day, and groupsize. The sample contains 414 observations, 81 in control, 87 in TC All, 95 in TC Best3, 69 in TC Best3 announced and 82 in TC Best1. 17 Table 1 reports the sample means by treatment group for pre-treatment characteristics and for baseline achievement in our sample. The table reports differences between treatment and control group means. There are no statistically significant differences in baseline performance and only a few statistically significant differences in other variables. A higher proportion of TC Best3, TC Best3 and TC Best1 were conducted in Mannheim due to a insufficient amount of applicants in Heidelberg. More sessions of TC All and TC Best1 than of Control were conducted in the afternoon. There are some weakly significant effects for Best1 with respect to the frequency of econ majors and sessions conducted in the morning. As shown below, including controls for pre-treatment characteristics as well as baseline performance does not alter the results. Figures 4 and 5 display the average improvement in performance between working periods 1 and 2. Performance refers to the number of correct clicks entered per minute. Figure 4 displays the main treatment effects. The Control group shows almost no difference in performance in the second period compared to the first. After an announced reward is assigned in TC Best3 announced, participants slack off. In contrast, all treatments with recognition show positive performance increases. In particular, when the reward is scarce, as is the case in TC Best3 and TC Best1, participants improve strongly. TC Best3 yields the strongest performance improvement. Figure 5 splits the sample up into recipients and non-recipients. Recipients of a thank-you card increase performance by half a click per minute in all treatments where the reward came as a surprise. Recipients in the announced treatment show lower performance in comparison to Control. Non-recipients of unannounced rewards also increase their performance. This increase is substantially larger than that of recipients and is the largest when the number of non-recipients is relatively small. Interestingly, the announced reward does not cause a performance increase. Taken together, the graphs suggest that an unannounced 16 Even though we do not think that this is likely, we cannot rule out that word spread and that participants in later sessions expected certain interventions. Therefore, the more salient treatments (TC Best3, TC Best3 announced, TC Best1) were conducted subsequent to the less salient treatments (Control, TC All) to make sure that we only positively surprised but not disappointed subjects with the intervention they received. 17 In total, 430 persons participated. Three sessions (two of Control and one of TC All had to be dropped from the analysis due to severe server breakdowns during working time. Moreover, two participants had to be excluded from the analysis; one participant was visually impaired, and an older participant was not able to work at a computer. 8

reward has positive effects on both recipients as well as non-recipients. Interestingly, the effect is larger for non-recipients than for recipients and larger when there are relatively many rewards. Moreover, all effects vanish and even reverse when the card is announced. For our main analysis, we use productivity measured as the number of correct entries per minute of worktime as the dependent variable. Specifically, we use correct entries as the outcome of interest since this is the variable the employer was most interested in. 18 Table 2 presents the main results, i.e. regressions on number of correct entries per minute in working period 2. Standard errors are clusterd on the session-level. We control for baseline performance by including productivity in working period 1 in all regressions to make sure that we only compare individuals with similar baseline performance. 19 Column I presents the overall treatment effects, column II additionally includes controls. Columns III and IV show the results split up by recipients and non-recipients. Scarce rewards (TC Best3 and TC Best1) have a statistically significant, positive effect on performance. TC Best3 increases performance by 1.1 clicks per minute, which corresponds to a performance increase by 7 % or a change of 2.66 standard deviations. In line with theory the increase in performance in TC Best 1 is smaller than the one in TC Best3 albeit not statistically significant (p=0.27, one sided). Handing a reward to all participants also increases performance, albeit less so than scarce rewards. While the effect is not statistically significant at conventional levels, it is significant at the 10 percent level in a one-sided test (p=0.06). Announced rewards have no overall effect on second period performance. As we control for baseline performance in all regressions, this could be driven by a relatively higher working period 1 effort so that participants had less room than in the other treatments to improve their performance. However, in contrast to Kosfeld and Neckermann (2011), we do not find an incentive effect of an announced non-material reward. A t-test on the difference in total productivity (quantity effect), the announcement of the thank-you card increases performance on the 10% level (p=0.08) in comparison to the control treatment. But this difference becomes insignificant when compared with first period performance in all other treatments, including control (p=0.34). 20 Hence, materially worthless rewards have a positive effect on overall work performance, but only when handed out spontaneously. Effect sizes are bigger for scarce than for non-scarce rewards, and relatively smaller when the reward is extremely scarce. As we hypothesized that the treatments will have different effects on recipients and non-recipients, we next turn to an analysis that looks at the different subgroups separately. The results are displayed in columns III and IV of Table 2 and show that the effects discussed above stem entirely from the non-recipients. Non-recipients in TC Best3 increase their performance 18 For a separate analysis of treatment effects on total quantity and quality output see further below in this section. 19 We also include baseline performance squared and cubic). 20 This is also the case if we run OLS regressions on performance in period 1 including control variables. 9

by 1.4 clicks per minute 21 in TC Best 3 and by about 1 click per minute in TC Best1. The performance changes of non-recipients in TC Best3 and TC Best1 are statistically different from each other on the 10% level (p=0.07, one-sided). This is in line with conformity theory, which argues that non-recipients should increase their performance after they find out that they perform below average and that this effect should be stronger when there are more rewards, i.e. when the signal of low performance associated with not receiving the reward is stronger. Receiving the reward has no statistically significant impact on performance in any of the treatments. 22 Nevertheless, all coefficients are positive, and in line with theory, we find that the coefficient in TC All is largest and close to statistical significance (p=0.06, one-sided). This supports the notion that conformity and reciprocity both affect the behavior of the recipients so that the effect is strongest in TC All, where there is no countervailing negative impact caused by conformity concerns to adjust performance downward. By the same logic, the coefficient in TC Best 3 is larger than the one in TC Best 1 as the information value decreases in the number of rewards although coefficients are not significantly different (p-value = 0.41, one-sided). Interestingly, both recipients as well as non-recipients in TC Best 3 announced have a statistically insignificant, negative coefficient, suggesting that neither mechanism is at work when the reward was announced ex ante. Apparently, receiving an announced reward does neither lead to reciprocity nor to conformity. Intuitively, this might be the case as an announced incentive might be perceived as a strategic instrument to induce higher effort rather than as a signal of kindness and recognition. At the same time, if we allow for heterogeneity in preferences for the reward, conformity concerns might be affected when not winning the reward is no longer a signal of below average performance, rather it signals below average preference for the reward, which might have less negative consequences for one s self-image. Table 3 in the Appendix shows treatment effects on quantity and quality separately where quality is measured as the error rate 23 Treatments affect quality levels somewhat but the sizes of the effects are small in comparison to what we observe for quantity. Moreover, quality levels were very high overall (only 1.6% of all entries were incorrect, s.d. = 2.7) so that all the treatment effects we have seen for correct entries are driven by changes in quantity not quality. Our results are robust to the inclusion of more controls for different time effects such as the day of week as well as whether the session took place during final exams period, during the semester or during semester break. Further, we run robustness checks on specifications 21 This corresponds to a performance increase by 9 percent or a change of 3.43 standard deviations. 22 We can rule out that top performers cannot increase their performance due to ceiling. In Bradler and Neckermann (2011) we use the same set-up and show that recipients do increase their performance subsequent to receiving a combination of reward and money. 23 The error rate is the number of errors made relative to the total number of clicks entered by a participant. Correctness of an individual entry is determined as whether or not it corresponds to what the majority of participants clicked as answer for this particular question. This serves as a very reliable quality measure because each survey was entered on average 286 times (s.d.=67). 10

including interaction terms of treatments with gender. The results stay qualitatively similar and depending on the specification coefficients even get slightly larger. 5 Conclusion This paper presents a natural field experiment to test ex-post effects of recognition. We contribute to the literature by studying the effect of recognition in a work setting and by looking at ex-post effects of rewards. We find that materially worthless rewards have a statistically significant impact on performance. Specifically, non-recipients increase their subsequent performance in response to scarce rewards. In line with conformity models that predict that subjects adjust their performance to correspond to average performance, this effect is larger when there is a relatively large number of recipients. We conclude that it is important to take ex-post effects of rewards into account and that channels like conformity produce unexpected effects that should be investigated further. Limitations of this study are the student sample, the short-term employment (no established relationship between employer and employees) and the short duration of the work. Future work should address these issues. 11

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Appendix Figure 2: Thank-you Card Figure 3: Screenshot - Data Entry Form 15

Figure 4: Difference in Performance by Treatment Improvement in correct entries (clicks/min).5 0.5 1 1.5 Control TC all TC best3 TC best3 ann. TC best1 Figure 5: Difference in Performance by Treatment and Performance Group Improvement in correct entries (clicks/min).5 0.5 1 1.5 Best3 Best1 Best3 ann. Recipients All Control Best3 ann. Best3 Best1 Non Recipients 16

Table 1: Summary Statistics by Treatment Group Control TC All TC Best3 TC Best3 ann. TC Best1 N 81 87 95 69 82 Female 0.593 0.552 0.558 0.565 0.659 (0.055) (0.054) (0.051) (0.060) (0.053) Econ major 0.600 0.512 0.634 0.667 0.457* (0.055) (0.054) (0.050) (0.057) (0.056) Mannheim 0.556 0.460 0.779*** 1.000*** 0.744** (0.056) (0.054) (0.043) (0.000) (0.048) Morning 0.407 0.299 0.389 0.406 0.268* (0.055) (0.049) (0.050) (0.060) (0.049) Afternoon 0.235 0.437*** 0.274 0.217 0.451*** (0.047) (0.053) (0.046) (0.050) (0.055) Evening 0.358 0.264 0.337 0.377 0.280 (0.054) (0.048) (0.049) (0.059) (0.050) Baseline performance 15.861 16.665 16.174 16.727 16.491 (0.342) (0.415) (0.431) (0.421) (0.414) Note: The Table reports means for each group. Standard deviations are displayed in parentheses. Significance levels indicate a difference of means (compared to the control group) and are denoted as follows: * p < 0.1, ** p < 0.05, *** p < 0.01. 17

Table 2: Treatment Effects on Productivity in Working Period 2 I II III IV TC All 0.708 0.792 0.677 0.757 (0.478) (0.500) (0.477) (0.501) TC Best3 1.146*** 1.048*** (0.384) (0.390) TC Best1 0.968** 0.957** (0.398) (0.406) TC Best3 announced -0.133-0.255 (0.478) (0.490) TC Best3-0.573 0.557 Recipients (0.515) (0.520) TC Best3-1.479*** 1.374*** Non-Recipients (0.399) (0.412) TC Best1-0.388 0.511 Recipients (0.791) (0.839) TC Best1-1.029*** 1.015** Non-Recipients (0.385) (0.406) TC Best3 announced - -0.323-0.372 Recipients (0.785) (0.791) TC Best3 announced - -0.061-0.172 Non-Recipients (0.484) (0.495) Constant 2.834 1.834 2.927 2.001 (2.698) (2.817) (2.836) (2.929) Controls Baseline Performance Yes Yes Yes Yes Demographics Yes Yes Other Controls Yes Yes Observations 414 409 414 409 Sessions 59 59 59 59 R 2 0.742 0.741 0.745 0.743 Note: This table reports OLS coefficient estimates (standard errors clustered by session are reported in parentheses). The dependent variable is productivity in working period 2 measured by correct clicks per minute where one click refers to checking a box on the computer screen to transfer the choice of survey participants into the database. Correct clicks are total clicks entered minus all errors made by the participant. TC All represents a thank-you card for all subjects. TC Best3 refers to sessions where three thank-you cards were assigned to the best three subjects. TC Best1 indicates sessions where only one thank-you card was given to the best subject. TC Best3 announced represents sessions where three thank-you cards have ben announced prior to working period 1. Treatment Control is omitted and serves as the reference category. Column I shows overall treatments effects with control for baseline performance where the latter is the productivity in working period 1. Further, we control for baseline performance squared and cubic. Column II includes controls for demographics such as gender and field of study as well as other controls such as location, time of day and groupsize. Column III and IV allow for a separate analysis for recipients and non-recipients of thank-you cards. Column IV additionally includes all control variables. Significance levels are denoted as follows: * p < 0.1, ** p < 0.05, *** p < 0.01. 18

Table 3: Treatment effects on Total Productivity and Error Rates in Working Period 2 I II III IV V VI Dep. Variable Total Clicks Total Clicks Total Clicks Total Clicks Error Rate Error Rate TC All 0.593 0.668 0.559 0.628-0.171-0.171 (0.466) (0.487) (0.467) (0.489) (0.191) (0.191) TC Best3 1.232*** 1.149*** 0.242 (0.393) (0.396) (0.209) TC Best1 0.994** 1.003** -0.154 (0.405) (0.411) (0.224) TC Best3 ann. -0.042-0.145 0.671 (0.480) (0.492) (0.500) TC Best3-0.559 0.558 0.220 Recipients (0.528) (0.528) (0.204) TC Best3-1.633*** 1.552*** 0.257 Non-Recipients (0.408) (0.418) (0.278) TC Best1-0.451 0.587-0.170 Recipients (0.814) (0.864) (0.249) TC Best1-1.051*** 1.061** -0.151 Non-Recipients (0.391) (0.408) (0.236) TC Best3 ann. - -0.233-0.264 0.633 Recipients (0.794) (0.798) (0.463) TC Best3 ann. - 0.027-0.054 0.695 Non-Recipients (0.475) (0.486) (0.738) Constant -2.881-3.833-3.139-4.033 1.686 1.688 (3.581) (4.186) (3.504) (4.051) (1.527) (1.534) Controls Baseline Yes Yes Yes Yes Yes Yes Performance Demographics Yes Yes Yes Yes Other Controls Yes Yes Yes Yes Observations 414 409 414 409 409 409 Sessions 59 59 59 59 59 59 R 2 0.742 0.741 0.746 0.744 0.077 0.077 Note: This table reports OLS coefficient estimates (standard errors clustered by session are reported in parentheses). In Columns I-IV, the dependent variable is the total number of clicks entered in the second working period where one click refers to checking a box on the computer screen to transfer the choice of survey participants into the database. In Columns V and VI, the dependent variable is the error rate in working period 2. The latter is calculated by total errors divided by total clicks entered. Detailed explanations on treatment dummies TC All, TC Best3, TC Best3 announced, TC Best1 can be found in Table 2. Treatment Control is omitted and serves as the reference category. All columns show treatments effects with control for baseline performance where the latter is the total productivity in working period 1 (with control for squared and cubic baseline performance) in columns I-IV, and respectively the error rate in working period 1 in columns V and VI. In Column I,II,IV and VI include controls for demographics such as gender and field of study as well as other controls such as location, time of day and groupsize. Column II, V and VI allow for a separate analysis for recipients and non-recipients of thank-you cards. Significance levels are denoted as follows: * p < 0.1, ** p < 0.05, *** p < 0.01. 19

Instructions Control: May I bother you a moment? I just talked to our IT-specialists. They did a brief check on our server. The data have been correctly transmitted from all computers so far. Thank-you card for all (TC All): May I bother you a moment? I just talked to our IT-specialists. They did a brief check on our server. The data have been correctly transmitted from all computers so far. We are glad that everything is going well, and would like to take the opportunity to thank you. In preparation for this data entry job, our president, Wolfgang Franz and we have decided to give everyone this thank-you card as a symbol of our appreciation and thankfulness for your support. Thank-you card for best 3 (TC Best3): May I bother you a moment? I just talked to our IT-specialists. They did a brief check on our server. The data have been correctly transmitted from all computers so far. We are glad that everything is going well, and we would like to take the opportunity to thank you. Our IT-specialists have told us that logins X, Y, and Z have transmitted most data so far. According to my notes, this should be Mr. /Mrs. X, Y, and Z, correct? In preparation for this data entry job, our president, Wolfgang Franz and we have decided to give everyone this thank-you card as a symbol of our appreciation and thankfulness for your support. However, Prof. Franz was only able to sign a small number of cards personally. Therefore, we have decided just now to hand these cards to those of you, who have shown particular commitment. Thank-you card for best 1 (TC Best1): May I bother you a moment? I just talked to our IT-specialists. They did a brief check on our server. The data have been correctly transmitted from all computers so far. We are glad that everything is going well, and we would like to take the opportunity to thank you. Our IT-specialists have told us that login X has transmitted most data so far. According to my notes, this should be Mr. /Mrs. X, correct? In preparation for this data entry job, our president, Wolfgang Franz and we have decided to give everyone this thank-you card as a symbol of our appreciation and thankfulness for your support. However, Prof. Franz was only able to sign a small number of cards personally. Therefore, we have decided just now to hand the card to that person who has shown particular commitment. 20

Thank-you card for best 3 - announced (TC Best3 announced): Together with the president of our institute, Prof. Franz, we have thought about something special we could do to thank you for your support. We decided to hand this thank-you card to every participant as a symbol of our appreciation. However, Prof. Franz was only able to sign a small number of cards personally. Therefore, we have decided just now to hand these cards to those three persons who will show particular commitment. Our IT will do a check on the server in about two hours anyway and can then tell me which three logins have transmitted most data up till then. Intervention: As I told you in the beginning, we want to hand over three thank-you cards, which the president of the institute has signed personally. These are logins X, Y, and Z, which should be Mr. /Mrs. X, Y, and Z, correct? Thank you again for your commitment and hard work. 21