When governments don’t like the numbers their statisticians report, they have two options. They can modify their policies with the aim of changing the trajectory of the economy. Or, they can push to change the data to conform to what they would like to see. In countries with trustworthy leaders, those who understand the value of objective facts, we see the former. In places where leaders think that facts are a matter of opinion, we all-too-often see the latter. Finding some economic facts inconvenient, President Trump’s inclination appears to be to change the data, not his policies.

Two recent news reports have been particularly troubling, one having to do with trade statistics and the other concerning growth forecasts....