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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)

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.

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.

We analyze data from a field experiment in which an auto repair firm provided checklists to mechanics and monitored their use. Revenue was 20 percent higher during the experiment, and the effect is equivalent to that of a 1.6 percentage point (10 percent) commission increase. Checklists appear to boost productivity by serving both as a memory aid and a monitoring technology. Despite the large benefits to the firm, mechanics did not use checklists without the firm directly monitoring their use. We show that a moral hazard can explain why mechanics do not otherwise adopt checklists. (JEL C93, D82, L25, L81)

We use an RCT to analyze the impacts of microcredit. The study population consists of loan applicants who were marginally rejected by an MFI in Bosnia. A random subset of these were offered a loan. We provide evidence of higher self-employment, increases in inventory, a reduction in the incidence of wage work and an increase in the labor supply of 16–19-year-olds in the household's business. We also present some evidence of increases in profits and a reduction in consumption and savings. There is no evidence that the program increased overall household income. (JEL C93, G21, I38, J23, L25, P34, P36)

This paper examines whether individual and team incentives can improve student learning and performance using a theoretical analysis and a randomized eld experiment. If individual incentives are provided to students based on a specied target or performance standard for all, on the one hand it may not work for the low-ability students if they perceive the target to be too high, while on the other hand the high-ability students will win the prizes without extra eort if the target is too low. Only students with an ability level close to the target will attempt to win by working harder. If the students are grouped in teams and evaluated based on the team average, incentives can have an eect for all students across the spectrum of ability, because the average team abilities are pushed toward the target and there is also an incentive to help each other within teams. A team incentive augmented with a tournament component may be even more desirable because it eliminates the target, inducing all teams to work harder, because they do not know what the quality and eort of their competitors will be. However, team incentives may be prone to free riding and coordination problems. This paper presents the results of a randomized eld experiment for a representative sample of 100 Beninese secondary schools to compare these three methods of incentivizing students.

Using date from a field experiment conducted in seventy Colombian municipalities, we investigate who pools risk with whom when risk pooling arrangements are not formally enforced. We explore the roles played by risk attitudes and network connections both theoretically and empirically. We find that pairs of participants who share a bond of friendship or kinship are more likely to (1) join the same risk pooling group and to (2) group assortatively with respect to risk attitudes. Also, consistent with our theoretical finding that when there is a problem of trust the process of pooling assortativley with respect to risk preferences is perturbed, we find (3) only weak evidence of such assorting among unfamiliar individuals.

The "Hawthorne effect," a concept familiar to all students of social science, has had a profound influence both on the direction and design of research over the past 75 years. The Hawthorne effect is named after a landmark set of studies conducted at the Hawthorne plant in the 1920s. The first and most influential of these studies is known as the "Illumination Experiment." Both academics and popular writers commonly summarize the results as showing that every change in light, even those that made the room dimmer, had the effect of increasing productivity. The data from the illumination experiments, however, were never formally analyzed and were thought to have been destroyed. Our research has uncovered these data. We find that existing descriptions of supposedly remarkable data patterns prove to be entirely fictional. There are, however, hints of more subtle manifestations of a Hawthorne effect in the original data.

Randomized experiments are increasingly used in development economics, with researchers now facing the question of not just whether to randomize, but how to do so. Pure random assignment guarantees that the treatment and control groups will have identical characteristics on average, but in any particular random allocation, the two groups will differ along some dimensions. Methods used to pursue greater balance include stratification, pair-wise matching, and re-randomization. This paper presents new evidence on the randomization methods used in existing randomized experiments, and carries out simulations in order to provide guidance for researchers. Three main results emerge. First, many researchers are not controlling for the method of randomization in their analysis. The authors show this leads to tests with incorrect size, and can result in lower power than if a pure random draw was used. Second, they find that in samples of 300 or more, the different randomization methods perform similarly in terms of achieving balance on many future outcomes of interest. However, for very persistent outcome variables and in smaller sample sizes, pair-wise matching and stratification perform best. Third, the analysis suggests that on balance the re-randomization methods common in practice are less desirable than other methods, such as matching.