MR Podcast: Our Favorite Models, Session 1

The Marginal Revolution Podcast is back and this time Tyler and I discuss some of our favorite models or ways of thinking about the world. We begin with Spence on Monopolies, Harberger on Incidence and Solow on Growth. Here’s one bit:

TABARROK: You have an increase in the corporate tax. What happens?

COWEN: One lesson of the Harberger model is actually anything can happen. Who bears the burden? Is it capital, is it labor, or is it consumers? In the simplest versions of the model, what you have is both a substitution, capital versus labor in the taxed sector, and you have substitutions across sectors. You have a whole series of different effects. One of the first and simplest lessons from Harberger, which is really neat, but people just hadn’t gotten it before, is if you tax the corporate sector under a lot of reasonably general assumptions, the rate of return on capital goes down equally in both sectors, which to us is standard fare.

What will happen is capital flows out of the corporate sector into the noncorporate sector, that lowers the marginal rate of return on capital in the nontaxed sector, and simply the notion of capital can suffer in both sectors. Again, a revelation, maybe self-evident to us having written this principles textbook, but it shocked people. The partial equilibrium models never show that.

TABARROK: When you tax the corporations, you’re also taxing the mom-and-pops.

COWEN: And the nonprofits and whatever, wherever else the capital might flow.

TABARROK: Yes. This was one of the first useful applications of general equilibrium.

COWEN: That’s right. On that, it’s really held up. International affairs, one of the lessons is if you turn the other sector or add another sector that’s international, basically small economies cannot afford to tax capital at very high rates because so much of the capital will flow elsewhere.

TABARROK: Instead of it flowing to the noncorporate sector, it just flows out of the country.

COWEN: That’s right, which is like the other sector not affected by this particular tax. In 1962, a lot of small economies treated their capital very badly. Many still do, but there’s been a real revolution where even fairly statist economies—like the Nordics over time shifted to treating capital income pretty generously. Singapore would be another example. Again, it’s simple once you know it, but the Harberger model taught us that.

TABARROK: What about the labor margin?

COWEN: The debate since then has been how much of the tax is borne by capital and how much is borne by labor? On one hand, the Harberger model teaches you anything can happen. That’s useful intuitively. In fact, when you investigate it empirically, it’s what you would expect to happen that mostly happens. That is, capital does bear more of the tax than labor.

TABARROK: Labor bears a chunk.

COWEN: Yes. A typical estimate might be a third. There’s no free lunch from the point of view of labor. Furthermore, a lot of the capital is owned by labor through pension funds. If you take that into account, I don’t have an exact number for you, but I think it’s plausible to think labor might bear half the burden of the corporate tax. Again, you can show that pretty simply. The estimates are not exact, but just a big advance for economics. If you ask me, what ideas do I use all the time, that’s one of them.

The Harberger basic model, it doesn’t have land, but there’s the issue of what if you have three factors in the model, you would start with the Harberger model. If you’re a NIMBY who thinks there’s this kind of land monopoly in a city or land rents are very high because we stifle building, the incidence of a lot of taxes, even in general equilibrium models, can fall on the land for a city.

TABARROK: Yes, because the land can’t escape.

COWEN: That’s right.

TABARROK: As we say in the textbook, elasticity is equal to escape, right?

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