“To understand human development, you have to understand the contexts that affect it. Sampson argues that neighborhood environments—not just the characteristics of people living in them—influence phenomena like crime, health, and learning.
Researchers also filmed Chicago block by block in what Sampson describes as a proto-Google Street View. Cruising in an SUV with tinted windows, at three to five miles an hour, his crew videotaped 23,816 street segments. They captured and logged both physical and social details: housing structures, garbage in the street, abandoned cars, broken windows, unsupervised kids, public drinking, prostitution, graffiti, drugs, arguments, police presence, even condoms on the street.
To examine altruism, Sampson fielded a “Lost Letter Experiment” in which researchers scattered stamped, addressed letters across neighborhoods and measured rates of return. To evaluate civic engagement, his team mined newspaper archives for events like protests or community breakfasts, amassing a database that spanned more than 30 years and 4,000 public gatherings.
Sampson took the social temperature of communities. One concept key to Sampson’s thinking is “collective efficacy,” a measure of how much people trust their neighbors and are willing to help them. In explaining a neighborhood’s level of criminal violence, Sampson has argued, collective efficacy is as important as—or even more important than—other characteristics, like poverty or physical disorder. .. No longer could we simply clean up the streets to get rid of the criminal element. We needed to promote, well, neighborliness”
But the question of neighborhood effects remains “hotly debated,” One knock on neighborhood-effects research is that it fails to account for a problem that scholars call “self-selection bias“—the effect of similar people clustering together.
Anyhow, “neighborhoods profoundly matter… the difference between living in a very poor neighborhood and a moderately middle-class neighborhood is as large as doubling your income in terms of happiness and well-being.”