Another Guest Post by Max Gödl, enjoy!
One argument I frequently hear in discussions on macro policy is that income inequality is a big drag on our economy right now. The reason is that rich folks save a larger fraction of their income than poor folks. Hence redistributing income from the top to the bottom increases aggregate spending which “grows the economy”. Let’s do it!
My response to that is: woah, woah, woah!
First of all, when presented in this way the argument is a non sequitur. It’s pretty clear that the rich have a higher average propensity to save than the poor. But that does not imply that their marginal propensity to save is higher, too. And it’s the latter that counts: Redistribution from rich to poor increases aggregate consumption only if the poor spend a larger fraction out of additional income than the rich. (Nerds, think Keynesian consumption function: C = a + bY. C/Y decreases with income, but dC/dY doesn’t!)
Now it turns out that the evidence on the marginal propensities to save of different income groups is surprisingly inconclusive. It has been known for ages that the positive correlation between current income and saving rates typically found in cross-sectional data doesn’t tell us anything about the relationship between saving rates and permanent income. There is a pretty large (but pretty old) literature, beginning with Milton Friedman’s classic 1957 work, showing that the MPS does not vary systematically with permanent income. So if income is measured over longer periods, the rich seem to save the same fraction out of additional income as the poor.
A more recent study by Dynan, Skinner and Zeldes (pdf) produces evidence that the rich actually do have a somewhat higher MPS than the poor. According to one of their estimates, the MPS of the bottom quintile of the income distribution is 16 percentage points lower than the MPS of the top quintile. And that’s their most generous estimate! Dynan et al. use U.S. data and I couldn’t find a similar study for Europe. Nevertheless, let’s take this number and think this through. The share of the top quintile in aggregate income is roughly 40 percent in the European Union, while the share of the bottom quintile is below 10 percent. If we would take 10 percentage points away from the top and give it to the bottom, aggregate consumption would increase by only 1.6 percent of aggregate income. So even a massive redistribution would only have a modest expansionary effect.
Finally, the expansionary redistribution hypothesis has an awkward implication. If shifting income from top to bottom increases aggregate spending, doing the opposite must decrease it. Do those who want to tax the rich and feed the poor to stimulate the economy in recessions also want to tax the poor and feed the rich during the boom years when the economy is overheating? I very much doubt it. But it would seem to be the logical implication of their theory.
There may be a good case for higher taxes on the rich and higher transfers to the poor. But we shouldn’t expect redistribution to get out of the recession.