(NYTIMES) In the late 1990s, Boston expanded its public pre-kindergarten programme, but it did not have nearly enough spots for every four-year-old in the city. To help determine which children could enrol, the city used a lottery. That lottery created a research opportunity.
It meant that thousands of otherwise similar children would have different life experiences based on random chance. And random chance is a powerful way for social scientists to study cause and effect. It may be the closest thing to a laboratory experiment in the real world.
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