Mike Konczal’s inequality post as a guest blogger for Ezra is getting a bit of attention in the blogosphere. Konczal jumps off of an interesting post by Jamelle Bouie to argue that contrary to those who argue that “inequality isn’t so bad,” the unhealthy nature of the cheaper food that is purchased by the poor negates the fact that the poor face a lower inflation rate. Since he suggests I (and Will Wilkinson) think that “inequality isn’t so bad,” I wanted to correct a misconception that Konczal has about the argument of economist Christian Broda that he is responding to. Broda’s actual argument really doesn’t have anything to do with how healthy the things purchased by the poor are.

Here’s Konczal:

One argument that has become popular recently is that the increase in income inequality isn’t quite as bad because both the rich and the poor have different ‘inflation’ rates — the prices at which goods increase for the rich have been increasing much faster than the prices at which goods have been increasing for the poor. So even though the poor or median person hasn’t had any wage growth, he has much more purchasing power because of this effect.

This isn’t quite the argument that has become popular recently. What fans of the Broda research argue (i.e., what Broda and his colleagues argue) is that the apparent increase in income inequality may overstate the actual increase in inequality because the poor appear to have a lower inflation rate than the rich. If true, then it’s not that “the poor or median person hasn’t had any wage growth,” it’s that they have had wage growth because of their lower inflation rate — and the wage growth has been big enough that it has kept the ratio of rich-to-poor incomes roughly constant.

Think of it this way. Broda and his colleagues find that the prices of what the poor buy (that is, “price” when the satisfaction derived, or utility, is held constant) have risen less than the prices of what the rich buy. That’s because when prices of related goods change, the poor are more likely to switch to cheaper goods, all the while maintaining their overall level of satisfaction with their purchases. If it becomes cheaper to maintain a constant level of satisfaction, then one’s wages have effectively grown. So poor consumers may switch from Green Giant frozen veggies to generics when the latter go on sale, or they might buy their frozen veggies at the chain a couple of neighborhoods over rather than the local grocery store when the latter’s prices go up. Rich consumers, on the other hand, may be relatively unlikely to stop buying Whole Foods vegetables when the plebian chain’s prices are cut. They may not switch to generics as those products become cheaper relative to those on offer at the farmer’s market.

It’s not that we should be excited about how great the generic frozen veggies bought by the poor are compared with the Whole Foods produce. It’s that we should be excited that the poor are either more willing or more able to economize to maintain a constant lifestyle than the rich are, and so inflation eats into their quality of life to a lesser extent than it does among the rich, holding in check other forces that would increase inequality.

Now, Broda’s research is based on purchases of a limited number of commodities and over a limited number of years, but if his findings extend to other goods and services and to earlier periods (which he believes they do), then the implication is that inequality between the poor and the well-off — though not necessarily the richest of the rich — has not grown. We can still worry about the quality of the food purchased by the poor and their health outcomes, but that’s a story about poverty and deprivation, not about inequality or growth in inequality.