How to measure Trump’s 100 days?

Tuesday marked the end of President Donald Trump’s first 100 days in office. Beginning on Day 90 or so, we’ve seen a slew of polls and pronouncements delivering judgment on the president’s performance. “HISTORICALLY UNPOPULAR,” read one headline on the Drudge Report. “LOWEST 100-DAY SCORE IN 80 YEARS!” read another. And another: “39% APPROVAL.”