What Is the Evidence on Taxes and Growth?
The idea that taxes affect economic growth has become politically contentious and the subject of much debate in the press and among advocacy groups. That is in part because there are competing theories about what drives economic growth. Some subscribe to Keynesian, demand-side factors, others Neo-classical, supply-side factors, while yet others subscribe to some mixture of the two or something entirely unique. The facts, historical and geographical variation in key parameters for example, should shed light on the debate. However, the economy is sufficiently complex that virtually any theory can find some support in the data.
For instance, the Congressional Research Service (CRS) has found support for the theory that taxes have no effect on economic growth by looking at the U.S. experience since World War II and the dramatic variation in the statutory top marginal rate on individual income. They find the fastest economic growth occurred in the 1950s when the top rate was more than ninety percent. However, their study ignores the most basic problems with this sort of statistical analysis, including: the variation in the tax base to which the individual income tax applies; the variation in other taxes, particularly the corporate tax; the short-term versus long-term effects of tax policy; and reverse causality, whereby economic growth affects tax rates. These problems are all well known in the academic literature and have been dealt with in various ways, making the CRS study unpublishable in any peer-reviewed academic journal.
So what does the academic literature say about the empirical relationship between taxes and economic growth? While there are a variety of methods and data sources, the results consistently point to significant negative effects of taxes on economic growth even after controlling for various other factors such as government spending, business cycle conditions, and monetary policy. In this review of the literature, I find twenty-six such studies going back to 1983, and all but three of those studies, and every study in the last fifteen years, find a negative effect of taxes on growth. Of those studies that distinguish between types of taxes, corporate income taxes are found to be most harmful, followed by personal income taxes, consumption taxes and property taxes.
These results support the Neo-classical view that income and wealth must first be produced and then consumed, meaning that taxes on the factors of production, i.e., capital and labor, are particularly disruptive of wealth creation. Corporate and shareholder taxes reduce the incentive to invest and to build capital. Less investment means fewer productive workers and correspondingly lower wages. Taxes on income and wages reduce the incentive to work. Progressive income taxes, where higher income is taxed at higher rates, reduce the returns to education, since high incomes are associated with high levels of education, and so reduce the incentive to build human capital. Progressive taxation also reduces investment, risk taking, and entrepreneurial activity since a disproportionately large share of these activities is done by high income earners.
Some of these items are long-term mechanisms, particularly human and physical capital formation. Most of these empirical studies focus on the long-term effects, over a period of five years or more, but many investigate short-term dynamics as well. The evidence for short-term, demand-side effects of tax policy is less robust and less compelling, perhaps owing to the difficulty of disentangling short-term factors and matching events. However, there is some evidence that longer-term, supply-side effects occur sooner than previously thought, such as within the first few years of a policy change.
In any case, the lesson from the studies conducted is that long-term economic growth is to a significant degree a function of tax policy. Our current economic doldrums are the result of many factors, but having the highest corporate rate in the industrialized world does not help. Nor does the prospect of higher taxes on shareholders and workers. If we intend to spur investment, we should lower taxes on the earnings of capital. If we intend to increase employment, we should lower taxes on workers and the businesses that hire them.