Economists and policymakers often debate the relationship between tax rates and tax revenue. Everyone essentially agrees that increasing rates will shrink the size of the economy but discouraging work and investment, but the question is will it shrink it by so much that it actually decreases federal revenue?
This piece in today’s Wall Street Journal presents evidence that regardless of the top marginal tax rates, federal revenue is pretty consistent as a share of GDP:
The federal tax “yield” (revenues divided by GDP) has remained close to 19.5%, even as the top tax bracket was brought down from 91% to the present 35%. This is what scientists call an “independence theorem,” and it cuts the Gordian Knot of tax policy debate.
The data show that the tax yield has been independent of marginal tax rates over this period, but tax revenue is directly proportional to GDP. So if we want to increase tax revenue, we need to increase GDP.
What happens if we instead raise tax rates? Economists of all persuasions accept that a tax rate hike will reduce GDP, in which case Hauser’s Law says it will also lower tax revenue. That’s a highly inconvenient truth for redistributive tax policy, and it flies in the face of deeply felt beliefs about social justice. It would surely be unpopular today with those presidential candidates who plan to raise tax rates on the rich – if they knew about it.
Although Hauser’s Law sounds like a restatement of the Laffer Curve (and Mr. Hauser did cite Arthur Laffer in his original article), it has independent validity. Because Mr. Laffer’s curve is a theoretical insight, theoreticians find it easy to quibble with. Test cases, where the economy responds to a tax change, always lend themselves to many alternative explanations. Conventional economists, despite immense publicity, have yet to swallow the Laffer Curve. When it is mentioned at all by critics, it is often as an object of scorn.
Because Mr. Hauser’s horizontal straight line is a simple fact, it is ultimately far more compelling. It also presents a major opportunity. It seems likely that the tax system could maintain a 19.5% yield with a top bracket even lower than 35%.
What makes Hauser’s Law work? For supply-siders there is no mystery. As Mr. Hauser said: “Raising taxes encourages taxpayers to shift, hide and underreport income. . . . Higher taxes reduce the incentives to work, produce, invest and save, thereby dampening overall economic activity and job creation.”
Unfortuantely, it seems that for many, soaking the rich is the purpose of raising taxes — it isn’t about getting more tax revenue at all. But for those who sincerely want to increase prosperity it seems this should be must reading.