In 1989, Hallam Hurt, a neonatologist in Philadelphia, started recruiting poor inner-city women for a study of how cocaine use during pregnancy affects the developing fetus. Dr. Hurt enrolled women who had used cocaine while pregnant and balanced them against a control group of equally poor women who had not taken any drugs. Years later, when the…

For roughly half a century, policymakers and researchers have debated the impacts of place, and in particular of inner-city neighborhoods, on employment, education, and mental and physical health. Research on programs that help people move to better neighborhoods has suggested that such programs can improve the life chances of low-income, mostly…