Babysitting and labor market outcomes

It is well established that what happens early in life matters a lot for adult outcomes. But some adult life choices may rather be influenced by event later in childhood, like what to study in college or which profession to take on, controlling for all the cognitive skills that seem to be largely set by then.

Zeynep Erdogan, Joyce Jacobsen and Peter Kooreman look at the impact of having worked as a teenager, and in particular as a babysitter, on fertility and labor market outcomes. Results are a mess, and I suspect that endogeneity and selection bias have a lot to do with it. The authors, though, find one rather strong result: Working during 10th grade has a positive impact on labor market outcomes and delays fertility. It is rather strange that having babysat (at a specific age) would encourage a woman to have children later. But babysitting in general leads to having more children, according to their results. That all looks like spurious correlations to me, especially as instrumental variable results looks very different from OLS ones.