Most panel data studies of intertemporal labor supply assume classical measurement error. Recent validation studies refute this assumption. In this study I address nonclassical measurement error explicitly. I use data on males from the Panel Study of Income Dynamics Validation Study to purge measurement error from the Panel Study of Income Dynamics. I find a large amount of predictable wage variation in the data, even after allowing for measurement error. However, there is almost no labor supply response to these predictable wage changes. Therefore, failure to control for nonclassical measurement error cannot explain the low estimated labor supply elasticities in other papers.

This article identifies the part‐time wage effect, using hours variation caused by the social security rules. We show that work hours and wages drop sharply at ages 62 and 65. We argue that the hours decline causes the wage decline, resulting in a 25% wage penalty for men who cut their work week from 40 to 20 hours. However, we find little evidence for such an effect among women. We also show that models that fail to account for the joint determination of hours and wages will understate the labor supply response to a tax change by about 26%.