Map of Sint-Pieters-Leeuw on This is a problem of missing data on wages for certain individuals. Heckman perceived that this problem of missing data is due to calculated decisions (selection) on the part of the individuals involved. In this example, people decide whether to stay in the labor force based on the costs and benefits. People who calculate that their utility is maximized by working will work, and people who calculate that their utility is maximized by retiring will retire. If one were to naively estimate the effect of age on wages by regressing wages on age for all workers, that calculation would suffer from selection bias, because at high ages, wages are likely only observed for people who have the highest earning potential. The challenge for the researcher is to find some way to adjust the estimates derived from a select sample to account for the selectivity of the sample. Heckman developed techniques to correct the econometric problems associated with sample selection. Map of Sint-Pieters-Leeuw 2016.
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