A recent study on the effect of minimum wages in the city of Seattle has produced some conflicted reactions. As most economists expected, the significant increase in the minimum wage resulted in job losses and bankruptcies. Others, however, doubt the validity of the results given that the sample may be incomplete.

In this post I want to focus just one empirical problem. An incomplete sample in itself may not be a problem. The issue is whether or not the observations missing from the sample are relevant. This problem has been pointed out before as the Russian Roulette Effect, which consists in asking survivors of the increase in minimum wages if the increase in minimum wages have put them out of business. Of course, the answer is no. In regards to Seattle, a concern might be that fast food chains such as McDonald’s are not properly included in the study.

The first reaction is, so what? Why is that a problem? If the issue is to show that an increase of wages above their equilibrium level is going to produce unemployment, all that has to be shown is that this actually happens, not to show where it does not happen. This concern about the Seattle study is missing a key point of the economic analysis of minimum wages. The prediction is that jobs will be lost first among less efficient workers and less efficient employers, not equally across all workers and employers. More efficient employers may be able to absorb a larger share of the wage increase, to cut compensations, delay the lay-offs, etc. This is seen by the fact that demand is downward sloping and that a minimum wage above its equilibrium level “cuts” demand in two. Some employers are below the minimum wage (the less efficient ones) and others are above the minimum wage (the more efficient ones.) Let’s call the former “Uncle’s diner” and the latter “McDonald’s.” This how it is seen in a demand and supply graph:

Surely, there is some overlapping. But the point that this graph is making is that looking at the effects minimum wage above the red line is looking at the wrong place. A study that is looking for the effect on employment needs to be looking at what happens with below the red line. This sample, of course, has less information available than fast food chains such as McDonald’s; this is a reason why some studies focus on what can be seen even if the effect happens in what cannot be seen (and this is a value added of the Seattle study.)

This is why it is important to ask: “what do minimum wage advocates expect to find by increasing the sample size?” To question that minimum wages increase unemployment, then the critics also needs to focus on the “Uncle’s diner” part of the demand curve. If the objective is to inquire about something else, than that has no bearing on the fact that minimum wage increases do produce unemployment in the minimum wage market and at the less efficient (and harder to gather data) portion of it first.

PS: I have a previous post on minimum wages that can be found here.