Third graders listen at the start of Lindsey Wuest's Science As Art class, at A.D. Henderson School in Boca Raton, Fla., on April 16, 2024.

Of course, retention wasn’t a totally empty threat in Michigan—more than 500 students were held back in 3rd grade in the 2021-22 school year, for example. The policy had unequal effects.