Steven D . Levitt

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Most papers that employ Differences-in-Differences estimation (DD) use many years of data and focus on serially correlated outcomes but ignore that the resulting standard errors are inconsistent. To illustrate the severity of this issue, we randomly generate placebo laws in state-level data on female wages from the Current Population Survey. For each law,(More)
E conomists have increasingly turned to the experimental model of the physical sciences as a method to understand human behavior. Peerreviewed articles using the methodology of experimental economics were almost nonexistent until the mid-1960s and surpassed 50 annually for the first time in 1982; and by 1998, the number of experimental papers published per(More)
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This paper identifies and evaluates rationales for team participation and for the effects of team composition on productivity using novel data from a garment plant that shifted from individual piece rate to group piece rate production over three years. The adoption of teams at the plant improved worker productivity by 14% on average. Productivity(More)
Between 1984 and 2001, the share of non-elderly adults receiving Social Security Disability Insurance income (DI) rose by 60 percent to 5.3 million beneficiaries. Rapid program growth despite improving aggregate health appears explained by reduced screening stringency, declining demand for less skilled workers, and an unforeseen increase in the earnings(More)
C rime fell sharply in the United States in the 1990s, in all categories of crime and all parts of the nation. Homicide rates plunged 43 percent from the peak in 1991 to 2001, reaching the lowest levels in 35 years. The Federal Bureau of Investigation’s (FBI) violent and property crime indexes fell 34 and 29 percent, respectively, over that same period.(More)
Agents are often better informed than the clients who hire them and may exploit this informational advantage. Real-estate agents, who know much more about the housing market than the typical homeowner, are one example. Because real estate agents receive only a small share of the incremental profit when a house sells for a higher value, there is an incentive(More)
We offer evidence that legalized abortion has contributed signiŽcantly to recent crime reductions. Crime began to fall roughly eighteen years after abortion legalization. The Žve states that allowed abortion in 1970 experienced declines earlier than the rest of the nation, which legalized in 1973 with Roe v. Wade. States with high abortion rates in the(More)
Most papers that employ Differences-in-Differences estimation (DD) use many years of data and focus on serially correlated outcomes but ignore that the resulting standard errors are inconsistent. To illustrate the severity of this issue, we randomly generate placebo laws in state-level data on female wages from the Current Population Survey. For each law,(More)
School choice has become an increasingly prominent strategy for enhancing academic achievement. To evaluate the impact on participants, we exploit randomized lotteries that determine high school admission in the Chicago Public Schools. Compared to those students who lose lotteries, students who win attend high schools that are better in a number of(More)