The National Council of Teachers of Mathematics (NCTM) may hold the title of promoting the most paradoxical anti-scientific and anti-intellectual practices. The NCTM formally rejected empirical studies that showed the effects of different teaching methods. Its basis for this rejection: "The results were disappointing." Imagine an organization that is supposed to understand math, which includes statistics, asserts in effect that mathematical truth is falsity.
The NCTM has supported a long list of failed practices. At the top of the list is "discovery learning." It doesn't seem to matter how many times or how thoroughly empirical evidence shows that this practice is ineffective.
-- Zig Engelmann