Papers - Natural

Puppe Clemens, Sebastian Kube, Michel Marechal

Cited by*: 18 Downloads*: 25

We study the role of reciprocity in a labor market field experiment. In a recent paper, Gneezy and List (2006) investigate the impact of gift exchange in this context and find that it has only a transient effect on long run outcomes. Extending their work to examine both positive and negative reciprocity, we find consonant evidence in the positive reciprocity condition: the gift does not work well in the long run (if at all). Yet, in the negative reciprocity treatment we observe much stronger effects: a wage reduction has a significant and lasting negative impact on efforts. Together, these results highlight the asymmetry of positive and negative reciprocity that exists in the field, and provide an indication of the relative importance of each in the long run.

Erwin Bulte, John A List, Mark Strazicich

Cited by*: 17 Downloads*: 2

Recent empirical work suggests that (i) incomes are converging through time, and (ii) income and pollution levels are linked. This paper weds these two literatures by examining the spatial and temporal distribution of pollution. After establishing that theoretical predictions about whether pollution will converge are critically linked to certain structural parameters, we explore pollution convergence using state-level data on two important pollutants-nitrogen oxides and sulfur oxides-from 1929 to 1999. We find stronger evidence of converging emission rates during the federal pollution control years (1970-1999) than during the local control years (1929-1969). These results suggest that income convergence alone may not be sufficient to induce convergence of pollutant emissions.

Peter A Riach, Judith Rich

Cited by*: 16 Downloads*: 52

Sexual discrimination in invitation to job interview was tested by a controlled experimental method of send ing carefully-matched pairs of letters in response to newspaper adver tisements-one from a female and one from a male applicant. On 363 of the occasions, when invitations were issued, the applicants were trea ted equally, but there were 144 occasions of differential treatment. Females encountered discrimination 40 percent more frequently than ma les. Discrimination against females was statistically significant for the data in aggregate and for two of the seven occupations involved- gardener and computer analyst-programmer.

Marco Haan, Peter Kooreman

Cited by*: 16 Downloads*: 11

A wealth of experimental literature studies the effect of repetition and group size on the extent of free riding in the provision of public goods. In this paper, we use data from honor systems for candy bars in 166 firms to test whether such effects can be found outside the laboratory. We find that free riding increases with repetition, and weak evidence that free riding decreases with group size.

Michael Kremer, Edward Miguel

Cited by*: 16 Downloads*: 19

We examine social learning using data from a program that promoted use of deworming medicine in Kenyan schools. These drugs kill worms in the body; although people are soon reinfected, treatment interferes with the cycle of transmission, generating positive externalities. Individuals randomly exposed to more information about deworming drugs through their social network were significantly less likely to take the drugs and more likely to believe the drugs are "not effective." This finding is consistent with the hypothesis that those exposed to the program had overly optimistic prior beliefs about net private drug benefits. The combination of strong social effects and extensive social networks among teenagers implies that a "child-to-child" public health approach focused on teenagers will speed social learning. There are large differences between social effect estimates relying on experimental variation (negative estimates) and nonexperimental methods (positive estimates).

Michael Kremer, Edward Miguel, Rebecca Thornton

Cited by*: 16 Downloads*: 13

We report results from a randomized evaluation of a merit scholarship program for adolescent girls in Kenya. Girls who scored well on academic exams had their school fees paid and received a cash grant for school supplies. Girls eligible for the scholarship showed significant gains in academic exam scores (average gain 0.12-0.19 standard deviations) and these gains persisted following the competition. There is also evidence of positive program externalities on learning: boys, who were ineligible for the awards, also showed sizeable average test gains, as did girls with low pretest scores, who were unlikely to win. Both student and teacher school attendance increased in the program schools. We discuss implications both for understanding the nature of educational production functions and for the policy debate surrounding merit scholarships.

Michael Kremer, Dan Levy

Cited by*: 16 Downloads*: 9

This paper examines a natural experiment in which students at a large state university were randomly assigned roommates through a lottery system. We find that on average, males assigned to roommates who reported drinking in the year prior to entering college had one quarter-point lower GPA than those assigned to non-drinking roommates. The 10th percentile of their college GPA is half a point lower than among males assigned non-drinking roommates. For males who themselves drank frequently prior to college, assignment to a roommate who drank frequently prior to college reduces GPA by two-thirds of a point. Since students who drink frequently are particularly influenced by frequent-drinking roommates, substance-free housing programs could potentially lower average GPA by segregating drinkers. The effect of initial assignment to a drinking roommate persists and possibly even grows over time. In contrast, students' college GPA is not influenced by roommates' high school grades, admission test scores, or family background. Females' GPAs are not affected by roommates' drinking prior to college. Overall, these findings are more consistent with models in which peers change preferences than models in which they change endowments.

Alan S Gerber, Donald P Green

Cited by*: 15 Downloads*: 45

We report the results of a randomized field experiment involving approximately 30,000 registered voters in New Haven, Connecticut. Nonpartisan get-out-the-vote messages were conveyed through personal canvassing, direct mail, and telephone calls shortly before the November 1998 election. A variety of substantive messages were used. Voter turnout was increased substantially by personal canvassing, slightly by direct mail, and not at all by telephone calls. These findings support our hypothesis that the long-term retrenchment in voter turnout is partly attributable to the decline in face-to-face political mobilization.

Dean S Karlan, Martin Valdivia

Cited by*: 15 Downloads*: 27

Most academic and development policy discussions about microentrepreneurs focus on credit constraints and assume that subject to those constraints, the entrepreneurs manage their business optimally. Yet the self-employed poor rarely have any formal training in business skills. A growing number of microfinance organizations are attempting to build the human capital of microentrepreneurs in order to improve the livelihood of their clients and help further their mission of poverty alleviation. Using a randomized control trial, we measure the marginal impact of adding business training to a Peruvian group lending program for female microentrepreneurs. Treatment groups received thirty- to sixty-minute entrepreneurship training sessions during their normal weekly or monthly banking meeting over a period of one to two years. Control groups remained as they were before, meeting at the same frequency but solely for making loan and savings payments. We find little or no evidence of changes in key outcomes such as business revenue, profits, or employment. We nevertheless observed business knowledge improvements and increased client retention rates for the microfinance institution.

John A List, Michael K Price

Cited by*: 15 Downloads*: 27

We explore collusion by using the tools of experimental economics in a naturally occurring marketplace. We report that competitive price theory adequately organizes data in multilateral decentralized bargaining markets without conspiratorial opportunities. When conspiratorial opportunities are allowed and contract prices are perfectly observed, prices (quantities) are considerably above (below) competitive levels. When sellers receive imperfect price signals, outcomes are intermediate to those of competitive markets and collusive markets with full information. Finally, experienced buyers serve as a catalyst to thwart attempts by sellers to engage in anticompetitive pricing: in periods where experienced agents transact in the market, average transaction prices are below those realized in periods where only inexperienced agents execute trades.

Dmitry Taubinsky, Alex Rees-Jones

Cited by*: 15 Downloads*: 31

This paper shows that accounting for variation in mistakes can be crucial for welfare analysis. Focusing on consumer underreaction to not-fully-salient sales taxes, we show theoretically that the efficiency costs of taxation are amplified by 1) individual differences in under reaction and 2) the degree to which attention is increasing with the size of the tax rate. To empirically assess the importance of these issues, we implement an online shopping experiment in which 2,998 consumers-matching the U.S. adult population on key demographics-purchase common household products, facing tax rates that vary in size and salience. We find that: 1) there are significant individual differences in underreaction to taxes. Accounting for this heterogeneity increases the efficiency cost of taxation estimates by at least 200%, as compared to estimates generated from a representative agent model. 2) Tripling existing sales tax rates roughly doubles consumers' attention to taxes. Our results provide new insights into the mechanisms and determinants of boundedly rational processing of not-fully-salient incentives, and our general approach provides a framework for robust behavioral welfare analysis.

Peter A Riach, Judith Rich

Cited by*: 15 Downloads*: 42

Racial discrimination in selection for job interview was measured directly by the experimental technique of "corresponding testing." Carefully-matched pairs of written job applications were sent in response to advertised vacancies in Victoria--a state of Australia. One letter was from an applicant with an Anglo-Celtic name and the other was from an applicant with a Greek or Vietnamese name. Statistically significant discrimination was found against both Vietnamese-named and Greek-named applicants. There was no relationship between the incidence of discrimination and the competitive structure of the employer's product market.

Michael Greenstone, John A List, Chad Syverson

Cited by*: 14 Downloads*: 1

The economic costs of environmental regulations have been widely debated since the U.S. began to restrict pollution emissions more than four decades ago. Using detailed production data from nearly 1.2 million plant observations drawn from the 1972-1993 Annual Survey of Manufactures, we estimate the effects of air quality regulations on manufacturing plants' total factor productivity (TFP) levels. We find that among surviving polluting plants, stricter air quality regulations are associated with a roughly 2.6 percent decline in TFP. The regulations governing ozone have particularly large negative effects on productivity, though effects are also evident among particulates and sulfur dioxide emitters. Carbon monoxide regulations, on the other hand, appear to increase measured TFP, especially among refineries. The application of corrections for the confounding of price increases and output declines and sample selection on survival produce a 4.8 percent estimated decline in TFP for polluting plants in regulated areas. This corresponds to an annual economic cost from the regulation of manufacturing plants of roughly $21 billion, about 8.8 percent of manufacturing sector profits in this period.

Stephen Benard, Shelley Correll, In Paik

Cited by*: 14 Downloads*: 104

Survey research finds that mothers suffer a substantial wage penalty, although the causal mechanism producing it remains elusive. The authors employed a laboratory experiment to evaluate the hypothesis that status-based discrimination plays an important role and an audit study of actual employers to assess its real-world implications. In both studies, participants evaluated application materials for a pair of same-gender equally qualified job candidates who differed on parental status. The laboratory experiment found that mothers were penalized on a host of measures, including perceived competence and recommended starting salary. Men were not penalized for, and sometimes benefited from, being a parent. The audit study showed that actual employers discriminate against mothers, but not against fathers.

John A List, Michael K Price

Cited by*: 14 Downloads*: 45

The economics literature suggests that enhanced social connection can increase trust amongst agents, which can ultimately lead to more efficient economic outcomes, including increased provision of public goods. This study provides a test of whether social connectedness (proxied via agent similarities in race and gender) influences giving to a charitable fundraiser. Using data gathered from more than 2000 households approached in an actual door-to-door fundraising drive, we find limited evidence of the importance of such social connections. A robust result in the data, however, is that our minority solicitors, whether approaching a majority or minority household, are considerably less likely to obtain a contribution, and conditional on securing a contribution, gift size is lower than their majority counterparts receive.

Armin Falk, Andrea Ichino

Cited by*: 14 Downloads*: 28

While confounding factors typically jeopardize the possibility to use observational data to measure peer effects, field experiments offer the possibility to obtain clean evidence. In this paper we measure the output of four randomly selected groups of individuals who were asked to fill letters in envelopes, with a remuneration completely independent of output. For two of these groups the output of peers was exogenously manipulated (low or high) by making individuals aware of the number of letters previously produced by artificial colleagues. In the third group individuals were set up to work one in front of the other, while the fourth group gave the baseline output for independent not manipulated work. Our first finding is that effort of the less productive workers reacts in a sizeable and statistically significant way to peer pressure. Second, there is strong evidence of peer effects when individuals work in pairs. Third, these peer effects work in the direction of making the least productive individuals work harder, thereby increasing overall productivity.

Stefano DellaVigna, John A List, Ulrike Malmendier, Gautam Rao

Cited by*: 13 Downloads*: 66

We design a model-based field experiment to estimate the nature and magnitude of workers' social preferences towards their employers. We hire 446 workers for a one-time task. Within worker, we vary (i) piece rates; (ii) whether the work has payoffs only for the worker, or also for the employer; and (iii) the return to the employer. We then introduce a surprise increase or decrease in pay ('gifts') from the employer. We find that workers have substantial baseline social preferences towards their employers, even in the absence of repeated-game incentives. Consistent with models of warm glow or social norms, but not of pure altruism, workers exert substantially more effort when their work is consequential to their employer, but are insensitive to the precise return to the employer. Turning to reciprocity, we find little evidence of a response to unexpected positive (or negative) gifts from the employer. Our structural estimates of the social preferences suggest that, if anything, positive reciprocity in response to monetary 'gifts' may be larger than negative reciprocity. We revisit the results of previous field experiments on gift exchange using our model and derive a one-parameter expression for the implied reciprocity in these experiments.

Yan Chen, Xin Li, Jeffrey K MacKie-Mason

Cited by*: 13 Downloads*: 11

We implemented the first web-based online field experiments of fund-raising. We embedded our experiment in the Internet Public Library to test four mechanisms: Voluntary Contribution (VCM), Premium, Seed Money and Matching. Although the gift size is not significantly different across mechanisms, the Seed and Matching mechanisms each generate significantly higher user click-through response rate than the Premium mechanism. Because this is one of the earliest embedded, web-based field experiments, we report our methodology findings in some detail. Cookies work better as participant assignment techniques than pop-up windows and elicitation of geographic information. Participant clickstream data that nominally demonstrate a desire to donate is a poor predictor of actual giving.

Michael Kremer, Sylvie Moulin, Robert Namunyu

Cited by*: 13 Downloads*: 9

Kenya's education system blends substantial centralization with elements of local control and school choice. This paper argues that the system creates incentives for local communities to build too many small schools; to spend too much on teachers relative to non-teacher inputs; and to set school fees that exceed those preferred by the median voter and prevent many children from attending school. Moreover, the system renders the incentive effects of school choice counterproductive by undermining the tendency for pupils to switch into the schools with the best headmasters. A randomized evaluation of a program operated by a non-profit organization suggests that budget-neutral reductions in the cost of attending school and increases in non-teacher inputs, financed by increases in class size, would greatly reduce dropout rates without reducing test scores. Moreover, evidence based on transfers into and out of program schools suggests that the population would prefer such a reallocation of expenditures.

Paul W Rhode, Koleman S Strumpf

Cited by*: 12 Downloads*: 16

Political stock markets have a long history in the United States. Organized prediction markets for Presidential elections have operated on Wall Street (1880-1944), the Iowa Electronic Market (1988-present), and TradeSports (2001-present). Proponents claim such markets efficiently aggregate information and provide forecasts superior to polls. An important counterclaim is that such markets may be subject to manipulation by interested parties. We analyze this argument by studying alleged and actual speculative attacks- large trades, uninformed by fundamentals, intended to change prices- in these three markets. We first examine the historical Wall Street markets where political operatives from the contending parties actively and openly bet on city, state and national races; the record is rife with accusations that parties tried to boost their candidates through investments and wash bets. Next we report the results of a field experiment involving a series of planned, random investments-- accounting for two percent of total market volume-- in the Iowa Electronic Market in 2000. Finally, we investigate the speculative attacks on TradeSports market in 2004 when a single trader made a series of large investments in an apparent attempt to make one candidate appear stronger. In the cases studied here, the speculative attack initially moved prices, but these changes were quickly undone and prices returned close to their previous levels. We find little evidence that political stock markets can be systematically manipulated beyond short time periods.