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We use a series of experiments to understand whether and how people’s beliefs about their own abilities are biased relative to the Bayesian benchmark and how these beliefs then affect behavior. We find that subjects systematically and substantially overweight positive feedback relative to negative (asymmetry) and also update too little overall (conservatism). These biases are substantially less pronounced in an ego-free control experiment. Updating does retain enough of the structure of Bayes’ rule to let us model it coherently in an optimizing framework, in which, interestingly, asymmetry and conservatism emerge as complementary biases. We also find that exogenous changes in beliefs affect subjects’ decisions to enter into a competition and do so similarly for more and less biased subjects, suggesting that people cannot “undo” their biases when the time comes to decide. This paper was accepted by Axel Ockenfels, behavioral economics and decision analysis. Funding: Financial support from the National Science Foundation (NSF), Harvard University, and Wesleyan University is gratefully acknowledged. P. Niehaus received financial support from an NSF Graduate Research Fellowship. Supplemental Material: The data files are available at https://doi.org/10.1287/mnsc.2021.4294 .

Pre-College human capital investment occurs within a competitive environment and depends on market incentives created by Affirmative Action (AA) in college admissions. These policies affect mechanisms for rank-order allocation of college seats, and alter the relative competition between blacks and whites. We present a theory of AA in university admissions, showing how the effects of AA on human capital investment differ by student ability and demographic group. We then conduct a field experiment designed to mimic important aspects of competitive investment prior to the college market. We pay students based on relative performance on a mathematics exam in order to test the incentive effects of AA, and track study efforts on an online mathematics website. Consistent with theory, AA increases average human capital investment and exam performance for the majority of disadvantaged students targeted by the policy, by mitigating so-called "discouragement effects." The experimental evidence suggests that AA can promote greater equality of market outcomes and narrow achievement gaps at the same time.

Typically, laboratory experiments suffer from homogeneous subject pools and self-selection biases. The usefulness of survey data is limited by measurement error and by the questionability of their behavioral relevance. Here we present a method integrating interactive experiments and representative surveys thereby overcoming crucial weaknesses of both approaches. One of the major advantages of our approach is that it allows for the integration of experiments, which require interaction among the participants, with a survey of non-interacting respondents in a smooth and inexpensive way. We illustrate the power of our approach with the analysis of trust and trustworthiness in Germany by combining representative survey data with representative behavioral data from a social dilemma experiment. We identify which survey questions intended to elicit people�s trust correlate well with behaviorally exhibited trust in the experiment. People above the age of 65, highly skilled workers and people living in bigger households exhibit less trusting behavior. Foreign citizens, Catholics and people favoring the Social Democratic Party or the Christian Democratic Party exhibit more trust. People above the age of 65 and those in good health behave more trustworthy or more altruistically, respectively. People below the age of 35, the unemployed and people who say they are in favor of none of the political parties behave less trustworthy or less altruistically, respectively.

We examine the gift exchange hypothesis on both the quantity and quality of output using a hybrid field-laboratory labor market experiment. We recruited participants to enter survey data for a well-known charitable organization. Workers were paid either a high or low wage. We find that although the total number of surveys entered did not vary with the wage, high wage workers made fewer errors and entered more surveys after controlling for errors. We further find that for low costs associated with errors, offering the low wage maximizes profits, but for higher costs paying the higher "gift exchange" wage maximizes profits.

Using data from three sources (a laboratory experiment, a field study, and a large US supermarket chain), we document a surprising asymmetric behavior of 9-ending prices: they are more rigid upward, but not downward, in comparison to non 9-ending prices. The data from the lab experiment and the field study suggest that shoppers are less likely to notice higher prices when they end with 9, or price increases when the new prices end with 9, in comparison to other endings. The consumers' misperception seems to be caused by their use of 9-endings as a signal for low prices, which interferes with price information processing. The supermarket data suggest that retail price setters respond strategically to the consumer misperception by setting 9-ending prices more often after price increases than after price decreases. 9-ending prices, therefore, usually increase only if the new prices are also 9-ending. Consequently, 9-ending prices exhibit asymmetric rigidity: they are more rigid than non 9-ending prices upward but not downward.

We present a lab-field experiment designed to systematically assess the external validity of social preferences elicited in a variety of experimental games. We do this by comparing behavior in the different games with several behaviors elicited in the field and with self-reported behaviors exhibited in the past, using the same sample of participants. Our results show that the experimental social preference games do a poor job explaining both social behaviors in the field and social behaviors from the past. We also include a systematic review and meta-analysis of previous literature on the external validity of social preference games. Data are available at https://doi.org/10.1287/mnsc.2017.2908 . This paper was accepted by John List, behavioral economics.

Inequality of opportunity, particularly when overlaid with socioeconomic, ethnic, or cultural differences, may limit the scope of cooperation between individuals. A central question, then, is how to overcome such obstacles to cooperation. We study this question in the context of Germany, by asking whether the propensity of immigrant youth to cooperate with native peers was affected by a major integration reform: the introduction of birthright citizenship. Our unique setup exploits data from a large-scale lab-in-the-field experiment in a quasi-experimental evaluation framework. We find that the policy caused male, but not female, immigrants to significantly increase their cooperativeness toward natives. We show that the increase in out-group cooperation among immigrant boys is an outcome of more trust rather than a reflection of stronger other- regarding preferences towards natives. In exploring factors that may explain these behavioral effects, we present evidence that the policy also led to a near-closure of the educational achievement gap between young immigrant men and their native peers. Our results highlight that, through integration interventions, governments can modify prosocial behavior in a way that generates higher levels of efficiency in the interaction between social groups.

We investigate how inviting students to set task-based goals affects usage of an online learning platform and course performance. We design and implement a randomized field experiment in a large mandatory economics course with blended learning elements. The low-cost treatment induces students to use the online learning system more often, more intensively, and to begin earlier with exam preparation. Treated students perform better in the course than the control group: they are 18.8% (0.20 SD) more likely to pass the exam and earn 6.7% (0.19 SD) more points on the exam. There is no evidence that treated students spend significantly more time, rather they tend to shift to more productive learning methods. The heterogeneity analysis suggests that higher treatment effects are associated with higher levels of behavioral bias but also with poor early course behavior.

Economists have traditionally assumed that individual behavior is motivated exclusively by extrinsic incentives. Social psychologists, in contrast, stress that intrinsic motivations are also important. In recent work, economic theorists have started to build psychological factors, like intrinsic motivations, into their models. Besley and Ghatak (2005) propose that individuals are differently motivated in that they have different "missions," and their self-selection into sectors or organizations with matching missions enhances organizational efficiency. We test Besley and Ghatak's model using data from a unique cohort study. We generate two proxies for intrinsic motivations: a survey-based measure of the health professionals’ philanthropic motivations and an experimental measure of their pro-social motivations. We find that both proxies predict health professionals' decision to work in the non-profit sector. We also find that philanthropic health workers employed in the non-profit sector earn lower wages than their colleagues.

This paper investigates the role of risk-aversion in the allocation of workers between formal and informal jobs in Ghana. In the model I propose risk-averse workers can opt between the free-entry informal sector and queuing for formal occupations. Conditional on identifying the riskier option, the model yields testable implications on the relationship between risk-preferences and workers’ allocation. My testing strategy proceeds in two steps. First, I estimate expected income uncertainty through panel data and find it significantly higher in the informal sector. Second, using novel experimental data to elicit individual attitudes to risk, I estimate the direct effect of risk-aversion on occupational choices and find that, in line with the first result, more risk-averse workers are more likely to queue for formal jobs and less likely to be in the informal sector. The results bear important implications for the optimal design of employment policies and social security.

Standard models of investment predict that credit-constrained firms should grow rapidly when given additional capital, and that how this capital is provided should not effect decisions to invest in the business or consume the capital. We randomly gave cash and in-kind grants to male- and female-owned microenterprises in urban Ghana. Our findings cast doubt on the ability of capital alone to stimulate the growth of female microenterprises. First, while the average treatment effects of the in-kind grants are large and positive for both males and females, the gain in profits is almost zero for women with initial profits below the median, suggesting that capital alone is not enough to grow subsistence enterprises owned by women. Second, for women we strongly reject equality of the cash and in-kind grants;\ud only in-kind grants lead to growth in business profits. The results for men also suggest a lower impact of cash, but differences between cash and in-kind grants are less robust. The difference in the effects of cash and in-kind grants is associated more with a lack of self-control than with external pressure. As a result, the manner in which funding is provided affects microenterprise growth.

Affirmative action to promote women's employment is a intensely debated policy. Do affirmative action policies attract women and does it come at a cost of deterring high qualified men? In three field experiments in Colombia we compare characteristics of job-seekers who are told of the affirmative action selection criterion before they apply with those who are only told after applying. We find that the gains in attracting female applicants far outweigh the losses in male applicants. Affirmative action is more effective in areas with larger female discrimination and deters male job-seekers from areas with low discrimination.

The stability of many post-conflict societies rests on the successful reintegration of former soldiers. We use an experimental approach to study reintegration in Northern Uganda and examine behavior of former soldiers together with the behavior of receiving communities towards this group. We focus on trust-based interactions and find that individual trustworthiness increases with the length of time a person was with the Lord's Resistance Army, a rebel group which forcibly recruited a large fraction of young people in the area. The effect is strongest among former soldiers who were abducted during childhood and is mute among those who soldiered during adulthood. These results are consistent with predictions of recent theories that highlight the importance of cooperation during war. Furthermore, members of receiving communities with an abductee son, who thus have better knowledge of former soldiers are aware of the behavioral difference. They believe former soldiers are more trustworthy than their peers and trust them more. Last, we find no evidence of preference-based discrimination, suggesting that anger is attenuated when communities do not attribute responsibility for committed violence to returning soldiers.

We present a new type of field experiment to investigate ethnic prejudice in the workplace. Our design allows us to study how potential discriminators respond to changes in the cost of discrimination. We find that ethnic discrimination is common but highly responsive to the “price of prejudice,” i.e., to the opportunity cost of choosing a less productive worker on ethnic grounds. Discriminators are on average willing to forego 8 percent of their earnings to avoid a coworker of the other ethnic type. The evidence suggests that animus rather than statistical discrimination explains observed behavior. (JEL C93, J15, J24, J31, J71)

This paper studies the interaction of incentive pay and social distance in the dissemination of information.We analyse theoretically as well as empirically the effect of incentive pay when agents have pro-social objectives,but also preferences over dealing with one social group relative to another. In a randomised field experiment under taken across 151 villages in South India,local agents were hired to spread information about a public health insurance programme.Relative to flat pay,incentive pay improves knowledge transmission to households that are socially distant from the agent,but not to households similar to the agent. public services,information constraints,incentive pay, social proximity,knowledge transmission

Although many countries are aggressively implementing the One Laptop per Child (OLPC) program, there is a lack of empirical evidence on its effects. This paper presents the impact of the first large-scale randomized evaluation of the OLPC program, using data collected after 15 months of implementation in 319 primary schools in rural Peru. The results indicate that the program increased the ratio of computers per student from 0. 12 to 1. 18 in treatment schools. This expansion in access translated into substantial increases in use both at school and at home. No evidence is found of effects on enrollment and test scores in Math and Language. Some positive effects are found, however, in general cognitive skills as measured by Raven’s Progressive Matrices, a verbal fluency test and a Coding test.

This paper reports the results of an experiment with secondary school students designed to improve their ability to reason, argument, and communicate using mathematics. These goals are at the core of many educational reforms. A structured pedagogical intervention was created that fostered a more active role of students in the classroom. The intervention was implemented with high fidelity and was internally valid. Students in the control group learned significantly more than those who received treatment. A framework to interpret this result is provided in which learning is the result of student-teacher interaction. The quality of such interaction deteriorated during the intervention.

Most experimental evidence of hyperbolic discounting is based on violations of either stationarity or time consistency. Stationarity is violated when intertemporal choices differ for trade-offs in the near versus the more distant future. Time consistency on the other hand is violated if the optimal allocation for specific dates changes over time. Both types of choice reversals may however also result from time-varying discount rates. Hyperbolic discounting is an unambiguous explanation for choice reversals only if individuals simultaneously violate both stationarity and time consistency. Our field experiment examines the extent to which this is the case. At different points in time, the same participants allocated a future gift over sooner-smaller and later-larger rewards with varying front-end delays. We find that most violations of time consistency do not coincide with violations of stationarity. Random noise in decision-making alone does not explain this finding. Instead, we find a significant association between individual violations and changes in household wealth, in particular for participants with less access to credit. We conclude that in a context of liquidity constraints, eliciting violations of either stationarity or time consistency alone is insufficient to identify hyperbolic discounting.

The use of directed giving – allowing donors to target their gifts to specific organizations or functions – is pervasive in fundraising, yet little is known about its effectiveness. We conduct a field experiment at a public university in which prospective donors are presented with either an opportunity to donate to the unrestricted Annual Fund, or an opportunity of donating to the Annual Fund and directing some or all of their donation towards the academic college from which they graduated. While there is no effect on the probability of giving, donations are significantly larger when there is the option of directing. However, the value of the option does not come directly from use, as very few donors choose to direct their gift.

We estimate the effects of one of the largest anti-vote-buying campaigns ever studied — with half a million voters exposed across 1427 villages—in Uganda’s 2016 elections. Working with civil society organizations, we designed the study to estimate how voters and candidates responded to their campaign in treatment and spillover villages, and how impacts varied with campaign intensity. Despite its heavy footprint, the campaign did not reduce politician offers of gifts in exchange for votes. However, it had sizable effects on people’s votes. Votes swung from well-funded incumbents (who buy most votes) towards their poorly-financed challengers. We argue the swing arose from changes in village social norms plus the tactical response of candidates. While the campaign struggled to instill norms of refusing gifts, it leveled the electoral playing field by convincing some voters to abandon norms of reciprocity—thus accepting gifts from politicians but voting for their preferred candidate.

We study how friendship shapes students' political opinions in a natural experiment. We use the indicator whether two students were exogenously assigned to a short-term "integration group", unrelated to scholar activities and dissolved before the school year, as instrumental variable for their friendship, to estimate the effect of friendship on pairwise political opinion outcomes in dyadic regressions. After six months, friendship causes a reduction of differences in opinions by one quarter of the mean difference. It likely works through a homophily-enforced mechanism, by which friendship causes politically-similar students to join political associations together, which reinforces their political similarity. The effect is strong among initially similar pairs, but absent in dissimilar pairs. Friendship affects opinion gaps by reducing divergence, therefore polarization and extremism, without forcing individuals' views to converge. Network characteristics also matter to the friendship effect.

We show that grit, a non-cognitive skill that has been shown to be highly predictive of achievement, is malleable in the childhood period and can be fostered in the classroom environment. Our evidence comes from an evaluation of a randomized educational intervention implemented in elementary schools in Istanbul. Outcomes are measured via a novel incentivized real effort task and actual school grades on core subjects. We find that treated students are 1) more likely to choose to undertake a more challenging and more rewarding task against an easier but less rewarding alternative, 2) less likely to give up after failure, 3) more likely to exert effort to accumulate task-specific ability, and consequently, 4) more likely to succeed and collect higher payoffs. The intervention also has a significant impact on school grades: We find that treated students are about 3 percentage points more likely to receive top grades in core academic subjects.

A housing lottery in an Indian city provided winning slum dwellers the opportunity to move into improved housing on the city’s periphery. Fourteen years later, relative to lottery losers, winners report improved housing farther from the city center, but no change in family income or human capital. Winners also report increased isolation from family and caste networks and lower access to informal insurance. We observe significant program exit: 34% of winners never moved into the subsidized housing and 32% eventually exited. Our results point to the importance of considering social networks when designing housing programs for the poor.Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.

This paper presents the results of three …eld experiments in an online labor market designed to determine whether referred workers perform better than non-referred workers and, if so, why. We hired workers and asked them to refer others; we then hired all referred and non-referred applicants. Referred workers performed better and had less turnover than non-referred workers. We …nd that this is partially due to selection: referrals outperformed non-referred workers even without any on-the-job interactions with their referrers. We …nd also that team production is important: referrals performed particularly well when working with their referrers.

Research on behavioral economics has established the importance of factors such as reference dependent preferences, hyperbolic discounting, and the value placed on non-financial rewards. To date, these insights have had little impact on the way the educational system operates. Through a series of field experiments involving thousands of primary and secondary school students, we demonstrate the power of behavioral economics to influence educational performance. Several insights emerge. First, we find substantial incentive effects from both financial and non-financial incentives on test scores. Second, we find that non-financial incentives are considerably more cost-effective than financial incentives for younger students, but were less effective with older students. Third, and perhaps most importantly, consistent with hyperbolic discounting, all motivating power of the incentives vanishes when rewards are handed out with a delay. Since the rewards to educational investment virtually always come with a delay, our results suggest that the current set of incentives may lead to underinvestment. Fourth, in stark contrast to previous laboratory experiments, we do not see an increased response of effort when rewards are framed as losses. Our findings imply that in the absence of immediate incentives, many students put forth low effort on standardized tests, which may create biases in measures of student ability, teacher value added, school quality, and achievement gaps.

Empirical social science relies heavily on self-reported data, but subjects may misreport behaviors, especially sensitive ones such as crime or drug abuse. If a treatment influences survey misreporting, it biases causal estimates. We develop a validation technique that uses intensive qualitative work to assess survey misreporting and pilot it in a field experiment where subjects were assigned to receive cash, therapy, both, or neither. According to survey responses, both treatments reduced crime and other sensitive behaviors. Local researchers spent several days with a random subsample of subjects after surveys, building trust and obtaining verbal confirmation of four sensitive behaviors and two expenditures. In this instance, validation showed survey underreporting of most sensitive behaviors was low and uncorrelated with treatment, while expenditures were under reported in the survey across all arms, but especially in the control group. We use these data to develop measurement error bounds on treatment effects estimated from surveys.

We conduct a field valuation experiment where we vary the valuation method (contingent valuation vs. inferred valuation) as well as the payment format (dichotomous choice vs. payment card). Willingness-to-accept and willingness-to-pay valuations are elicited in a within-subjects design for foods with climate neutral labels. We find a similar gap for valuations elicited with the contingent or the inferred valuation method. However, we also find that the gap can be muted by using a payment card elicitation format.

We investigate whether and how time pressure affects performance. We conducted a field experiment in which students from an Italian University are proposed to choose between two exam schemes: a standard scheme without time pressure and an alternative scheme consisting of two written intermediate tests, one of which to be taken under time pressure. Both exam schemes consist of a verbal and a numerical part, each carrying half of the total marks. Students deciding to sustain the alternative exam are randomly assigned to a "time pressure" and a "no time pressure" group. Students performing under time pressure at the first test perform in absence of time pressure at the second test and vice versa. We find that being exposed to time pressure exerts a negative and statistically significant impact on students' performance both at the verbal and at the numerical task. The effect is driven by a strong negative impact on females' performance, while there is no statistically significant effect on males. Gender differences in handling time pressure are relevant only when dealing with the verbal task. Using data on students' expectations, we also find that the effect produced by time pressure on performance was correctly perceived by students. Female students expect a lower grade when working under time pressure, while males do not.

In the television show Affari Tuoi a contestant is endowed with a sealed box containing a monetary prize between one cent and half a million euros. In the course of the show the contestant learns more information about the distribution of possible monetary prizes inside her box. Consider two groups of contestants, who learned that the chances of their boxes containing a large prize are 20% and 80% correspondingly. Contestants in both groups receive qualitatively similar price offers for selling the content of their boxes. If contestants are less risk averse when facing unlikely gains, the price offer is likely to be more frequently rejected in the first group than in the second group. However, the fraction of rejections is virtually identical across two groups. Thus, contestants appear to have identical risk attitudes over (large) gains of low and high probability.

Regulation fostering Managed Care alternatives in health insurance is spreading. This work reports on an experiment designed to measure the amounts of compensation asked by the Swiss population (in terms of reduced premiums) for Managed-Care type restrictions in the provision of health care. It finds that restrictions on the freedom of physician choice would require an average compensation of more than one-third of the premium, while generic substitution even meets with a small willingness to pay. Marked preference heterogeneity is an argument against regulation imposing uniformity of contract in Swiss social health insurance.

This paper uses the experimental setup of Tanaka et al. (2010) to measure refugees’ risk preferences. A sample of 206 asylum seekers was interviewed in 2017-18 in Luxembourg. Contrary to studies which focus on risk aversion in general, we analyze its components using a cumulative prospect theory (CPT) frame-work. We show that refugees exhibit particularly low levels of risk aversion compared to other populations and that CPT provides a better fit for modelling risk attitudes. Moreover, we include randomised temporary treatments provoking emotions and find a small significant impact on probability distortion. Robustness of the Tanaka et al. (2010) experimental framework is confirmed by including treatments regarding the embedding effect. Finally, we propose a theoretical model of refugee migration that integrates the insights from our experimental outcomes regarding the functional form of refugees’ decision under risk and the estimated parameter values. The model is then simulated using the data from our study

Fungibility of money is a central assumption in the theory of consumer choice: any unit of money is substitutable for another. This implies that the composition of income or wealth is irrelevant for consumption. We find that even in a simple, incentivized setup many subjects do not treat money as fungible. When a label is attached to a part of their budget, subjects change consumption according to the label. We first provide suggestive evidence from the field and then use a laboratory experiment to show this result in a tightly controlled environment. In the lab, subjects with lower cognitive abilities are more likely to violate fungibility. The findings lend support to behavioral models of narrow bracketing and mental accounting. One implication of our results is that in-kind benefits distort consumption more strongly than usually assumed. (JEL: C91, C93, D01, H31, I38)

In this study, we consider how gift-exchange and bonus systems function in a natural field setting by measuring the effort response of participants to non-monetary gifts over time. Our field experiment tests the difference in effort response to unconditional gifts delivered immediately, promised unconditional gifts delivered later, and conditional gifts linked to reaching a specific performance target. We find important benefits from promising to give an unconditional gift later: participants respond positively to a promised gift twice by increasing effort when the gift is promised and again when it is received. A promised gift outperforms both the unconditional gift delivered immediately, which leads to a single positive response, and the conditional gift based on performance, which does not trigger any significant behavioural change after the gift is delivered. The study lends insights into the relative effectiveness of gift-exchange and bonus systems and the temporal structure of reciprocal exchange.

Significant income gains from migrating from poorer to richer countries have motivated unilateral (source-country) policies facilitating labor emigration. However, their effectiveness is unknown. The authors conducted a large-scale randomized experiment in the Philippines testing the impact of unilaterally facilitating international labor migration. The most intensive treatment doubled the rate of job offers but had no identifiable effect on international labor migration. Even the highest overseas job-search rate that was induced (22 percent) falls far short of the share initially expressing interest in migrating (34 percent). The paper concludes that unilateral migration facilitation will at most induce a trickle, not a flood, of additional emigration.

Boys are doing worse in school than are girls, which has been dubbed “the Boy Crisis.” An analysis of the latest data on educational outcomes among boys and girls reveals extensive disparities in grades, reading and writing test scores, and other measurable educational outcomes, and these disparities exist across family resources and race. Focusing on disadvantaged schoolchildren, I then examine whether time investments made by boys and girls related to computer use contribute to the gender gap in academic achievement. Data from several sources indicate that boys are less likely to use computers for schoolwork and are more likely to use computers for playing games, but are less likely to use computers for social networking and email than are girls. Using data from a large field experiment randomly providing free personal computers to schoolchildren for home use, I also test whether these differential patterns of computer use displace homework time and ultimately translate into worse educational outcomes among boys. No evidence is found indicating that personal computers crowd out homework time and effort for disadvantaged boys relative to girls. Home computers also do not have negative effects on educational outcomes such as grades, test scores, courses completed, and tardies for disadvantaged boys relative to girls.

This paper reports the results from a controlled field experiment designed to investigate the causal effect of unannounced, public recognition on employee performance. We hired more than 300 employees to work on a three-hour data-entry task. In a random sample of work groups, workers unexpectedly received recognition after two hours of work. We find that recognition increases subsequent performance substantially, and particularly when recognition is exclusively provided to the best performers. Remarkably, workers who did not receive recognition are mainly responsible for this performance increase. Our results are consistent with workers having a preference for conformity and being reciprocal at the same time. Data, as supplemental material, are available at http://dx.doi.org/10.1287/mnsc.2015.2291 . This paper was accepted by John List, behavioral economics.

Many families fail to vaccinate their children despite the supply of these services at no cost. This study tests whether personal reminders can increase demand for vaccination. A field experiment was conducted in rural Guatemala in which timely reminders were provided to families whose children were due for a vaccine. The six-month intervention increased the probability of vaccination completion by 2.2 percentage points among all children in treatment communities. Moreover, for children in treatment communities who were due to receive a vaccine, and whose parents were expected to be reminded about that due date, the probability of vaccination completion increased by 4.6 percentage points. The cost of an additional child with complete vaccination due to the intervention is estimated at about $7.50.

We conducted a field experiment involving 720 Italian undergraduate students to investigate the existence of gender differences in performance in competitive settings and whether performance is affected by one's opponent gender. The experimental design was aimed at neutralizing other differences in psychological attitudes, such as self-confidence and risk aversion, that are typically considered as potential explanations of gender differences in competitive environments. Students were invited to undertake a midterm exam under a tournament scheme having as a prize some bonus points to add to the final grade. Students competed in pairs of equal predicted ability but different gender composition. In a competitive setting in which risk aversion, feedback provision and self-confidence have little relevance, we find that women tend to perform similarly to men. The gender of one's competitor does not play any role in shaping students’ behavior. Men and women perform similarly both in the competitive and in the non-competitive environment.

How to hire voluntary helpers? We shed new light on this question by reporting a field experiment in which we invited 2859 students to help at the ‘ESA Europe 2012’ conference. Invitation emails varied non-monetary and monetary incentives to convince subjects to offer help. Students could apply to help at the conference and, if so, also specify the working time they wanted to provide. Just asking subjects to volunteer or offering them a certificate turned out to be significantly more motivating than mentioning that the regular conference fee would be waived for helpers. By means of an online-survey experiment, we find that intrinsic motivation to help is likely to have been crowded out by mentioning the waived fee. Increasing monetary incentives by varying hourly wages of 1, 5, and 10 Euros shows positive effects on the number of applications and on the working time offered. However, when comparing these results with treatments without any monetary compensation, the number of applications could not be increased by offering money and may even be reduced.

Tax evasion is a pervasive problem in many countries. In particular, some developing countries do not collect even half of what they would if taxpayers complied with the written letter of the law. The academic literature has not been oblivious to the need to explain why people pay (or do not pay) taxes. However, the empirical literature has not yet reached consensus. This paper reports the results of a large field experiment that tried to affect compliance by influencing property tax taxpayers’ beliefs regarding the levels of enforcement, reciprocity, and peer-effects of the tax system in a municipality in Argentina. Results indicate that those taxpayers that received the deterrence message have a higher probability (almost 5 percentage points) to comply than the taxpayers in the control group. No average effects are found for the other two treatments. However, this average effects masks important results. After receiving the reciprocity and the peer-effects messages, the probability of compliance increased for some taxpayers but it decreased for others according to their underlying distribution of beliefs. The evidence in this paper advances the state of knowledge, may help to reconcile some of the results in the literature, and provides the basis for advancing policies and research on tax compliance in developing countries.

This discussion paper led to a publication in the Journal of Labor Economics . We conduct a field experiment in a large retail chain to test basic predictions of tournament theory regarding prize spread and noise. A random subset of the 208 stores participates in two-stage elimination tournaments. Tournaments differ in the distribution of prize money across winners of the first and second round of the tournament. As predicted by theory, we find that a more convex prize spread increases performance in the second round at the expense of first-round performance, although the magnitude of these effects is small. Moreover, the treatment effect is significantly larger for stores that historically have relatively stable performance as compared to stores with more noisy performance.

We conducted an experiment with 182 inmates from a maximum security prison to analyze the impact of criminal identity salience on cheating. The results show that inmates cheat more when we exogenously render their criminal identity more salient. This effect is specific to individuals who have a criminal identity, because an additional placebo experiment shows that regular citizens do not become more dishonest in response to crime-related reminders. Moreover, our experimental measure of cheating correlates with inmates’ offenses against in-prison regulation. Together, these findings suggest that criminal identity salience plays a crucial role in rule violating behavior.

In this paper, we compare participants in an artefactual field experiment in urban China with the survey population of migrants from which they were recruited. The experimental participants were more educated, more likely to lend money to friends, and worked fewer hours than the general population. They differ significantly from non-participants in terms of regression coefficients, such as the effects of wealth and marital status on the probability of being self-employed and distance migrated. We thus find that there was selection into our experiments on the basis of both observable characteristics and on unobserved differences in behavioral relations.

© 2015 Elsevier Inc. We explore the role of experience in mixed-strategy games by comparing, for a stylized version of Texas Hold-em, the behavior of experts, who have extensive experience playing poker online, to the behavior of novices. We find significant differences. The initial frequencies with which players bet and call are closer to equilibrium for experts than novices. And, while the betting and calling frequencies of both types of subjects exhibit too much heterogeneity to be consistent with equilibrium play, the frequencies of experts exhibit less heterogeneity. We find evidence that the style of online play transfers from the field to the lab.

No behavior sits in a vacuum, and one behavior can greatly affect what happens next. We propose a conceptual frame within which a broad range of behavioral spillovers can be accounted for when applying behavioral science to policy challenges. We consider behaviors which take place sequentially and are linked, at a conscious or unconscious level, by some underlying motive. The first behavior leads to another behavior which can either work in the same direction as the first (promoting spillover), or push back against it (permitting or purging spillover). Looking through this conceptual lens at the existing evidence, we find pervasive evidence for all kinds of spillover effects across a variety of fields and domains. As a result, behavioral scientists, especially those seeking to inform policy, should try to capture all the ripples from one behavior to the next when a pebble of intervention is thrown in the pond, and not just at the immediate behavioral splash it makes.

We conduct a remittance field experiment among Salvadoran migrants in the metro DC area. Migrants need to decide whether or not to remit funds to a recipient in El Salvador and if so how much. We maintain a (2×2) design in which the remittance budget has a value of $400 or $200, and the remitted funds arrive as cash or grocery vouchers that are non-transferable and applicable to basic necessities that do not include alcohol and cigarettes. Each migrant is randomly allocated to one of the resulting four treatments. We test across these treatments whether control over remittance spending in the form of grocery vouchers affects remittance behavior. We find the following. Our quantitative findings suggest that migrants prefer a remittance to arrive as cash than as groceries when stakes are high. This result is robust to inclusion of a wide set of covariates and is consistent with a conceptual framework in which migrants have preferences over how recipients spend remittances. Our qualitative findings suggest that migrants integrate amounts sent in the experiment with the external environment for sending remittances. We explore the mechanisms underlying the main effect and find that migrants who more recently sent a remittance and, in certain specifications, male migrants exhibit a greater preference for cash. Some implications of our findings are discussed.

“Site selection bias” can occur when the probability that a program is adopted or evaluated is correlated with its impacts. I test for site selection bias in the context of the Opower energy conservation programs, using 111 randomized control trials involving 8.6 million households across the United States. Predictions based on rich microdata from the first 10 replications substantially overstate efficacy in the next 101 sites. Several mechanisms caused this positive selection. For example, utilities in more environmentalist areas are more likely to adopt the program, and their customers are more responsive to the treatment. Also, because utilities initially target treatment at higher-usage consumer subpopulations, efficacy drops as the program is later expanded. The results illustrate how program evaluations can still give systematically biased out-of-sample predictions, even after many replications.

This paper examines firms’ incentives to develop a new (green) product, which might compete against the pollutant (brown) good that they traditionally sell. We show that in equilibrium more than one firm might develop a green product, but such an equilibrium outcome is not necessarily efficient. In particular, we predict an excessive amount of green goods under certain conditions, namely, when the green product is extremely clean but both products are not sufficiently differentiated in their attributes, and when the green product is not significantly cleaner than the brown good. We finally provide policies that help regulatory authorities promote equilibrium outcomes yielding the highest social welfare.

We conduct experiments with adolescent participants on repeated fixed play in three different zero-sum games which have mixed strategy minimax solutions. Further, we collect subject information on cognitive abilities and participation rates in competitive activities. We find the adolescents' correspondences with and deviations from minimax play largely consistent with previously and widely studied adult populations. Further, we find strategic sophistication in terms of implementation of the mixed minimax strategy as well as earnings are not correlated with cognitive ability nor previous experience in competitive situations.

Market outcomes depend on the quality of information available to its participants. We measure the effect of information disclosure on market outcomes using a large-scale field experiment that randomly discloses quality information in wholesale automobile auctions. We argue that buyers in this market are horizontally differentiated across cars that are vertically ranked by quality. This implies that information disclosure helps match heterogeneous buyers to cars of varying quality, causing both good and bad news to increase competition and revenues. The data confirm these hypotheses. These findings have implications for the design of other markets, including e-commerce, procurement auctions, and labor markets. (JEL C93, D44, D82, L15)