A Simple Explanation for a Strange Paradox: Why the US Economy Grew Faster When Tax Rates Were High, and Grew Slower When Tax Rates Were

by Mike Kimel

A Simple Explanation for a Strange Paradox: Why the US Economy Grew Faster When Tax Rates Were High, and Grew Slower When Tax Rates Were Low
Cross posted at the Presimetrics blog.

If you are familiar with my writing, you know that for years I have been covering the proverbial non-barking dog: the textbook relationship between taxes and economic growth, namely that higher marginal rates make the economy grow more slowly, is not borne out in real world US data.

Sure, there are a whole raft of academic studies that claim to show just that, but all of them, without fail, rely on rather heroic assumptions, and most of them throw in cherry picked data sets to boot. Leaving out those simple assumptions tends to produce empirical results that fail to abide by the most basic economic theory. This is true for data at the national level and at the state and local level.

Making matters more uncomfortable (and thus explaining all the heroic assumptions and cherry picking of data in the academic literature) is that the correlations between tax rates and economic growth are actually positive. That is to say, it isn’t only that we do not observe any relationship between tax rates and economic growth, in general it turns out that faster economic growth accompanies higher tax rates, not lower ones, and doesn’t take fancy footwork to show that. A few simple graphs and that’s that.

Now, obviously I sound like a lunatic writing this because it goes so far against the grain, but a) I’ve been happy to make my spreadsheets available to any and all comers, and b) others have gotten the same results on their own. Being right in ways that are easily checkable mitigates my being crazy (or a liar, for that matter), but it doesn’t change the uncomfortable fact that data requires a lot of torture before conforming to theory. And yet, that’s the road most economists seem to take, which explains why economics today is as useless as it is. It also speaks poorly of economists. The better approach is come up with theory that fits the facts rather than the other way around.

I’ve tried a few times to explain the relationship that I’ve pointed out so many times, but I never came up with anything that felt quite right. I think I have it now, and it’s very, very simple. Here goes.

Assumptions:
1. Economic actors react to incentives more or less rationally. (Feel free to assume “rational expectations” if you have some attachment to the current state of affairs in macro, but it won’t change results much.)
2. There is a government that collects taxes on income. (Note – In a nod to the libertarian folks, we don’t even have to assume anything about what the government does with the taxes. Whether the government burns the money it collects in a bonfire, or uses it to fund road building and control epidemics more efficiently than the private sector can won’t change the basic conclusions of the model.)
3. People want to maximize their more or less smoothed lifetime consumption of stuff plus holdings of wealth. More or less smoothed lifetime consumption means that if given the choice between more lifetime consumption occurring, with the proviso that it happens all at once, or a bit less lifetime consumption that occurs a bit more smoothly over time, they will generally prefer the latter. Stuff means physical and intangible items. People also like holding wealth at any given time, even if they don’t plan to ever spend that wealth, because wealth provides safety, security, and prestige, and for some, the possibility of passing on some bequest.

(If the first two look familiar, they were among 8 assumptions I used last week in an attempt to get where I’m going this time around. Note that I added two words to the second assumption. More on last week’s post later.)

Due to assumptions 1 and 3, people will want to minimize their tax burden at any given time subject provided it doesn’t decrease their lifetime consumption of stuff plus holdings of wealth. Put another way – all else being equal, peoples’ incentive to avoid/evade taxes is higher when tax rates are higher, and that incentive decreases when tax rates go down. Additionally, most people’s behavior, frankly, is not affected by “normal” changes to tax rates; raise or lower the tax rates of someone getting a W-2 and they can’t exactly change the amount of work they do as a result. However, there are some people, most of whom have high actual or potential incomes and/or a relatively large amount of wealth, for whom things are different. For these people, some not insignificant amount of their income in any year comes from “investments” or from the sort of activities for which paychecks can be dialed up or down relatively easily. (I assume none of this is controversial.)

Now, consider the plight of a person who makes a not insignificant amount of their income in any year comes from “investments” or from the sort of activities for which paychecks can be dialed up or down relatively easily, and who wants to reduce their tax burden this year in a way that won’t reduce their total more or less smoothed lifetime consumption of stuff and holdings of wealth. How do they do that? Well, a good accountant can come up with a myriad of ways, but in the end, there’s really one method that reigns supreme, and that is reinvesting the proceeds of one’s income-generating activities back into those income-generating activities. (i.e., reinvest in the business.) But ceteris paribus, reinvesting in the business… generates more income in the future, which is to say, it leads to faster economic growth.

To restate, higher tax rates increase in the incentives to reduce one’s taxable income by investing more in future growth.

A couple acknowledgements if I may. First, I would like to thank the commenters on my last post at the Presimetrics and Angry Bear blogs, as well as Steve Roth for their insights as they really helped me frame this in my mind.

Also, I cannot believe it took me this long to realize this. My wife and I are certainly not subject to the highest tax rate, and yet this is a strategy we follow. At the moment, we are able to live comfortably on my income. As a result, proceeds from the business my wife runs get plowed back into the business. This reduces our tax burden, and not incidentally, increases our expected future income.