The effect of taxation on labour supply: the case of moonlighting

The authors provide a simple test of supply-side economics by estimating the responsiveness of moonlighting labour supply to changes in the marginal tax rate and the wage rate. While standard theory teachers that changes in taxes and wage should have opposite and equal effects on labour supply, taxes affect the entire asset position of the household. In the short run, an adjustment of hours in the second job may be the only option available to an individual in responding to a tax change. Thus, analyses based on after-tax wages may understate supply-side effects. To estimate these effects a tobit procedure is employed. The empirical results suggest a backward-bending supply curve over thet range of moonlighting hours. Data consist of a subsample of male blue-collar workers from the 1978 cross-section of the Panel study of Income Dynamics.