Most Popular Books by Steven D Levitt

This study presents an overview of modern field experiments and their usage in economics. Our discussion focuses on three distinct periods of field experimentation that have influenced the economics literature. The first might well be thought of as the dawn of quot;fieldquot; experimentation: the work of Neyman and Fisher, who laid the experimental foundation in the 1920s and 1930s by conceptualizing randomization as an instrument to achieve identification via experimentation with agricultural plots. The second, the large-scale social experiments conducted by government agencies in the mid-twentieth century, moved the exploration from plots of land to groups of individuals. More recently, the nature and range of field experiments has expanded, with a diverse set of controlled experiments being completed outside of the typical laboratory environment. With this growth, the number and types of questions that can be explored using field experiments has grown tremendously. After discussing these three distinct phases, we speculate on the future of field experimental methods, a future that we envision including a strong collaborative effort with outside parties, most importantly private entities.

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 for them to convince their clients to sell their houses too cheaply and too quickly. We test these predictions by comparing home sales in which real estate agents are hired by others to sell a home to instances in which a real estate agent sells his or her own home. In the former case, the agent has distorted incentives; in the latter case, the agent wants to pursue the first-best. Consistent with the theory, we find homes owned by real estate agents sell for about 3.7 percent more than other houses and stay on the market about 9.5 days longer, even after controlling for a wide range of housing characteristics. Situations in which the agent''s informational advantage is larger lead to even greater distortions.

The main results of the paper are as follows: Information in the National Crime Victimization Survey suggests that property crime victimization has become increasingly concentrated on the poor. For instance, in the mid-1970s households with incomes below $25,000 (in 1994 dollars) were actually burglarized slightly less than households with incomes greater than $50,000. By 1994, the poor households were 60 percent more likely to be burglarized than the rich households. For violent crime, however, a different pattern is observed. In the Chicago homicide data, homicide rates at a point in time are generally inversely related to median family income in the community. However, this relationship has substantially weakened over time for blacks and has disappeared completely for whites by 1990. This finding is particularly striking because cross-neighborhood income inequality increased substantially over the time period examined. In other words, the income gap between the richest and poorest communities grew substantially, but the murder gap shrunk.