Nine conservative economists write in the Wall Street Journal that tax reform along the lines of what congressional Republicans are considering could boost average annual GDP growth by 0.4 percent. If we would have 1.9 percent average annual growth without tax reform, for example, we would have 2.3 percent with it.
That may not sound like much–it’s less than half what Commerce Secretary Wilbur Ross was touting a few weeks ago–but it’s nothing to sneeze at. If my math is right, it would mean we would have an economy roughly $900 billion larger ten years from now. But there’s also some reason to believe that the economists are overestimating the positive effect of reform by more than a factor of two.