In my previous post, I argued that the wage gap — the difference in income between similarly situated men and women — is more important an issue than generally regarded. In addition to its sexist nature, the wage gap significantly contributes to poverty. On the most extreme end, the incidence of poverty among single mothers would drop by more than half (from 25.3 percent to 12.6 percent) if the wage gap were closed. This fact raises an issue not addressed in the previous post: how should we talk about poverty and inequality with respect to single mothers?

Conservatives try to pin poverty and the increase in inequality on the decline of marriage and rise of single parenting. On its face, the marriage point is a curious one as lower rates of marriage do not correspond to higher levels of inequality in international comparisons. Leaving that glaring theoretical defect aside for the moment, the wage gap point raises yet another tricky issue of how we talk about causation. What does it mean when a conservative says lower marriage rates and the rise of single parenting cause higher poverty and inequality? Presumably, they mean something like: all other things equal, ticking up marriage rates and ticking down single motherhood rates would decrease poverty and inequality.

But if we used that standard for proving causation, then any number of things can be said to cause the higher rates of poverty and inequality. Relevant in this case is the following claim: all other things equal, ticking down the wage gap spread would decrease poverty and inequality. That is a true statement. So does the wage gap cause poverty? We could go further: all other things equal, increasing transfer programs would decrease poverty and inequality. That too is a true statement. So, where does that leave us on diagnosing the cause of poverty? The answer is that — as with most issues dealing with multiple sufficient causes — it does not really leave us anywhere.

Instead of quibbling uselessly and incoherently about the true cause of poverty and inequality, we should be asking ourselves which poverty-reducing and inequality-reducing changes are the best. The long-term, cross-country trend shows a clear declining preference for marriage. Most sensible people, I assume, do not favor forcing people to enter into domestic relationships and household forms that they no longer desire. As such, we are only left with changing our institutions to reflect modern household formation norms, and the eminently reasonable policy of eliminating widespread wage discrimination. Those seem like clear winners to me.