A percentage was misstated in James R. Delisle’s Commentary “Differentiation Doesn’t Work,” in the Jan. 7, 2015, issue of Education Week. According to a 2008 study by the Thomas B. Fordham Institute, 83 percent of teachers nationwide said differentiation was “somewhat” or “very” difficult to implement.
A version of this article appeared in the January 14, 2015 edition of Education Week as Correction
