At Cafe Hayek, Don Boudreaux has an excellent post on models and their usefulness in economics. Don’s gist is as follows:
Anyone can devise a model to show almost anything. And economics is filled with widely referenced models that are useless (or worse than useless). The Keynesian Cross comes to mind. So, too, the textbook model of so-called “perfect competition” (which, in addition to being a model in which almost everything resembling real-world competition is either squeezed out or appears as a monopolizing (!) tactic, isn’t even logically coherent – for in the model no room exists for any agent actually to change prices).
The value of an economic model is found in its ability to make the world more understandable. Devising a model is no evidence that the named concepts in the model have anything in reality to correspond to them, or that the model is a useful analytical tool.
I have made similar points in the past, noting that the results from models are, well, model-dependent.
In short, the mere fact that a model can show that some preferred policy will increase/decrease economic efficiency doesn’t mean said model is of any analytical use. Sure, the minimum wage in a monopsony may improve the situation, but that information does us no good if the market is not a monopsony.
But let’s build upon this idea. Let’s assume, for the sake of argument, that a given market where a minimum wage is considered is indeed a monopsony. As such, it is theoretically possible that minimum wage would be beneficial, that we would not see, over a given price range, a decline in employment. The poor economist stops here. He might even advocate for minimum wage at this point. But, as Bastiat reminds us, the economist looks for not just the seen effects (ie, what the model says), but the unseen effects, too. The good economist is prompted now to ask “is minimum wage the most cost-effective solution to the problem we are trying to address (in this case, low wages for workers)?” Minimum wage may be an option here, but it may not be the most beneficial option! There may be other options, other institutional arrangements, other agreements that can be reached that will create a better outcome!
Gordon Tullock and James Buchanan drive this point home in their 1962 book The Calculus of Consent. The following is from page 61 of the Liberty Fund Edition of the book (original emphasis):
The most important implication that emerges from the [analytical] approach taken here [in this chapter] is the following: The existance of external effects of private behavior is neither a necessary nor a sufficient condition for an activity to be placed in the realm of collective choice.
While Tullock and Buchanan are discussing externalities here, we can easily generalize their comment to any form of collective action including minimum wage or other methods used to “improve” monopsonies: The existence of a monopsony market resulting from private behavior is neither a necessary nor sufficient condition for a minimum wage to be imposed. The burden of proof requires the good economist to demonstrate that any proposed solution is the best of all available options. Otherwise, the result of the market process, even if less-than-ideal, may be the best choice.
It is easy to play around with models, and any given model may have any number of policy implications. But the mere fact the model suggests Policy A would work doesn’t necessarily mean that Policy A is the best choice. If the costs of imposing A are high, then it may likely end up being a net loss!