Joel Slemrod, LSA professor of economics, told the New York Times it will be difficult, if not impossible, to know the long-term impact of last year’s tax-reform act on the American economy. The co-author of a study of the 1986 tax-reform act, Slemrod said, “It’s not like chemistry or physics where you can do a controlled experiment and change one variable. We can never be entirely sure because we don’t know what would have happened without the tax act.”

Slemrod made his comments to columnist James B. Stewart, who was seeking to assess President Donald Trump’s claim, in last week’s State of the Union address, that the recent tax-reform bill was responsible for the nation’s strong economy, low unemployment, and surging stock market. Slemrod is a past consultant to the U.S. Treasury and the World Bank, among other institutions.

Click here to read more from Joel Slemrod on the Trump tax-reform bill and the economy.