Yesterday, here at Notes on Liberty, Nicolas Cachanosky blogged about the minimum wage. His point was fairly simple: criticisms against certain research designs that use limited sample can be economically irrelevant.

To put you in context, he was blogging about one of the criticisms made of the Seattle minimum wage study produced by researchers at the University of Washington, namely that the sample was limited to “small” employers. This criticism, Nicolas argues, is irrelevant since the researchers were looking for those who were likely to be the most heavily affected by the minimum wage increase since it will be among the least efficient firms that the effects will be heavily concentrated. In other words, what is the point of looking at Costco or Walmart who are more likely to survive than Uncle Joe’s store? As such, this is Nicolas’ point in defense of the study.

I disagree with Nicolas here and this is because I agree with him (I know, it sounds confused but bear with me).

The reason is simple: firms react differently to the same shock. Costs are costs, productivity is productivity, but the constraints are never exactly the same. For example, if I am a small employer and the minimum wage is increased 15%, why would I fire one of my two employees to adjust? If that was my reaction to the minimum wage, I would sacrifice 33% of my output for a 15% increase in wages which compose the majority but not the totality of my costs. Using that margin of adjustment would be insensible for me given the constraint of my firm’s size. I might be more tempted to cut hours, cut benefits, cut quality, substitute between workers, raise prices (depending on the elasticity of the demand for my services). However, if I am a large firm of 10,000 employees, sacking one worker is an easy margin to adjust on since I am not constrained as much as the small firm. In that situation, a large firm might be tempted to adjust on that margin rather than cut quality or raise prices. Basically, firms respond to higher labor costs (not accompanied by greater productivity) in different ways.

By concentrating on small firms, the authors of the Seattle study were concentrating on a group that had, probably, a more homogeneous set of constraints and responses. In their case, they were looking at hours worked. Had they blended in the larger firms, they would have looked for an adjustment on the part of firms less to adjust by compressing hours but rather by compressing the workforce.

This is why the UW study is so interesting in terms of research design: it focused like a laser on one adjustment channel in the group most likely to respond in that manner. If one reads attentively that paper, it is clear that this is the aim of the authors – to better document this element of the minimum wage literature. If one seeks to exhaustively measure what were the costs of the policy, one would need a much wider research design to reflect the wide array of adjustments available to employers (and workers).

In short, Nicolas is right that research designs matter, but he is wrong in that the criticism of the UW study is really an instance of pro-minimum wage hike pundits bringing the hockey puck in their own net!