Rational Irrationality: Do Good Kindergarten Teachers Raise their Pupils' Wages? : The ... - 0 views
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Columnist David Leonhardt reports the findings of a new study which suggests that children who are fortunate enough to have an unusually good kindergarten teacher can expect to make roughly an extra twenty dollars a week by the age of twenty-seven.
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it implies that during each school year a good kindergarten teacher creates an additional $320,000 of earnings.
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The new research (pdf), the work of six economists—four from Harvard, one from Berkeley, and one from Northwestern—upends this finding. It is based on test scores and demographic data from a famous experiment carried out in Tennessee during the late nineteen-eighties, which tracked the progress of about 11,500 students from kindergarten to third grade. Most of these students are now about thirty years old, which means they have been working for up to twelve years. The researchers also gained access to income-tax data and matched it up with the test scores. Their surprising conclusion is that the uplifting effect of a good kindergarten experience, after largely disappearing during a child’s teen years, somehow reappears in the adult workplace. (See Figure 7 in the paper.) Why does this happen? The author don’t say, but Leonhardt offers this explanation: “Good early education can impart skills that last a lifetime—patience, discipline, manners, perseverance. The tests that 5-year-olds take may pick up these skills, even if later multiple-choice tests do not.”
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However, as I read the story and the findings it is based upon, some questions crept into my mind. I relate them not out of any desire to discredit the study, which is enterprising and newsworthy, but simply as a warning to parents and policymakers not to go overboard.
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from a dense academic article that hasn’t been published or peer reviewed. At this stage, there isn’t even a working paper detailing how the results were arrived at: just a set of slides. Why is this important? Because economics is a disputatious subject, and surprising empirical findings invariably get challenged by rival groups of researchers. The authors of the paper include two rising stars of the economics profession—Berkeley’s Emmanuel Saez and Harvard’s Raj Chetty—both of whom have reputations for careful and rigorous work. However, many other smart researchers have had their findings overturned. That is how science proceeds. Somebody says something surprising, and others in the field try to knock it down. Sometimes they succeed; sometimes they don’t. Until that Darwinian process is completed, which won’t be for another couple of years, at least, the new findings should be regarded as provisional.
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A second point, which is related to the first, concerns methodology. In coming up with the $320,000 a year figure for the effects that kindergarten teachers have on adult earnings, the authors make use of complicated statistical techniques, including something called a “jack knife regression.” Such methods are perfectly legitimate and are now used widely in economics, but their application often adds an additional layer of ambiguity to the findings they generate. Is this particular statistical method appropriate for the task at hand? Do other methods generate different results? These are the sorts of question that other researchers will be pursuing.