http://www.angrybearblog.com/2010/12/why-economy-stubbornly-insists-on.html?utm_source=twitterfeed&utm_medium=twitterI've been writing for years about the fact that a basic piece of economic theory does not apply to real world US data: unless one engages in the sort of assumptions that can justify eating ceramic plates as a cure for leprosy, there is simply no evidence that lower taxes lead to the good stuff we've been led to believe over non-cherry picked data sets. Recent examples include this look at the effect top federal marginal rates on various measures of growth, this look at the effect of top federal marginal rates on tax revenues, a different look at federal marginal rates and growth, and this look using state tax levels. I've also shown that effective tax rates also have fail to cooperate with theory when looking over the length of presidential administrations - examples include myriad posts and Presimetrics, the book I wrote with Michael Kanell.
I think the reason a lot of people have trouble accepting this is that they see some sort of conflict between this macro fact and and what seems to be a self-evident micro truth - if tax rates get high enough, people will work less. Now, such micro-macro conflicts have existed in the past, and are certainly aren't unique to economics. One obvious example we all live with is that to each of us, from where we're standing, the Earth does a pretty good job of appearing to be flat, and yet we know that its actually round(ish). For most applications, from running a marathon to building a house to making toast, assuming that the earth is flat doesn't hurt, and even simplifies matters. That is to say, for most applications facing critters roughly our physical size, a flat earth is a good model. On the other hand, we'd be much impoverished by sticking to that model at all times, as we'd lose out on satellites, our understanding of weather and geology, a great deal of transoceanic shipping, and Australia.
The same thing is true when it comes to the economy - failing to understand and account for the dichotomy between micro and macro truths is harmful. It has cost us, all 6.8 billion of us, economic growth and wealth, which is to say, it has cost us in quality and length of life.
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But that is one single player. In a big enough economy, there can be many, many companies and/or individuals of many different sizes in just such a situation. With 310 million people and who knows how many companies in the economy, probabilities add up. (I note that the second benefit of biasing companies toward their largest available projects goes away when you consider the whole economy. After all, while company X saves on accountants/attorneys and economists by picking the larger projects, by leaving the smaller projects to smaller players, those players will be hiring accountants/attorneys and economists as well.)
Note that relaxing a few assumptions makes it even easier to understand why US macro data shows a positive correlation between marginal tax rates and real economic growth. For instance, it isn't difficult to imagine that the government actually does something useful (i.e., growth generating) with the some of the tax money it collects. Additionally, smaller firms are often more innovative than larger firms, even within the same space (one has to compete somehow). Our little story is one where under many circumstances, smaller firms are more likely to enter the market when tax rates rise than when tax rates fall.
Thus, this little story, while requiring only a few realistic assumptions, does something that as far as I know is unique in the field of economics: it explains why US macro data shows a positive correlation between the top marginal tax rates and economic growth for all but the most cherry picked data sets, and it does it by sticking to micro foundations.