Seeing Double

This blog has occasionally highlighted the shortcomings of some bloggers and others when it comes to mathematics, but over in the US, the Trump administration has managed to make a $2 trillion error in their proposed budget:

Trump has promised to enact “the biggest tax cut in history.” Trump’s administration has insisted, however, that the largest tax cut in history will not reduce revenue, because it will unleash growth. That is itself a wildly fanciful assumption. But that assumption has already become a baseline of the administration’s budget math. Trump’s budget assumes the historically yuge tax cuts will not lose any revenue for this reason — the added growth it will supposedly generate will make up for all the lost revenue.

But then the budget assumes $2 trillion in higher revenue from growth in order to achieve balance after ten years. So the $2 trillion from higher growth is a double-count. It pays for the Trump cuts, and then it pays again for balancing the budget. Or, alternatively, Trump could be assuming that his tax cuts will not only pay for themselves but generate $2 trillion in higher revenue. But Trump has not claimed his tax cuts will recoup more than 100 percent of their lost revenue, so it’s simply an embarrassing mistake.

It seems difficult to imagine how this administration could figure out how to design and pass a tax cut that could pay for itself when Ronald Reagan and George W. Bush failed to come anywhere close to doing so. If there is a group of economic minds with the special genius to accomplish this historically unprecedented feat, it is probably not the fiscal minds who just made a $2 trillion basic arithmetic error.

I liked author Jonathan Chait's last paragraph and sentence there. It seems perfectly logical to me to base your opinion on someone's credibility on the evidence available. I'm glad to see others thinking in the same way.