Labor Supply

The response of the quantity of labor supplied to the real wage depends on both an income effect and a substitution effect. When the substitution effect is larger than the income effect, the supply curve has the “normal” upward-sloping shape. In the end, the shape of the labor supply curve is an empirical question; we can answer it only by going to the data. And as you might be able to guess, it turns out to be a difficult question to answer, once we start dealing with the complexities of different kinds of labor. The view of most economists who have studied labor supply is that higher real wages do lead to a greater quantity of labor supplied, but the effect is not very strong. The income effect almost cancels out the substitution effect. This means that the labor supply curve slopes upward but is quite steep. The Effect of the Reagan Tax Cuts on the Supply of Labor Suppose an individual knows the nominal wage but also knows that she is going to be taxed on any income that she earns at the going income tax rate. The wage rate that matters for her decision is the after-tax real wage. Her real disposable income is

disposable income = hours worked × (1 − tax rate) × ( nominal wage

price level )

= hours worked × (1 − tax rate) × real wage. All our discussion of labor supply continues to hold in this case, except that we need to replace the real wage with the after-tax real wage since it is the after-tax wage that matters to the individual. Figure 12.11 “Labor Supply Response to Tax Cut” shows the effect of a cut in taxes. If the labor supply curve slopes upward, the tax cut leads to an increase in the quantity of labor supplied. And if labor supply increases, then potential output also increases. In other words, one effect of tax cuts is to induce people to work harder and produce more real GDP. To keep things simple, Figure 12.11 “Labor Supply Response to Tax Cut” is drawn supposing that there is no change in the equilibrium real wage as a result of the tax cut. In fact, we would expect the real wage to decrease somewhat as well. Buyers of labor as well as sellers of labor would benefit from the tax cut. Indeed, it is this decrease in the real wage that induces firms to purchase the extra labor that individuals wish to supply.