From that article:

> however, when qualified by IQ and reading levels, Strategy Instruction (SI) had better effects for the high IQ group.

Which only goes to show that being a great teacher is an impossible mission, and it's wonderful how many succees at it despite the difficulty.

DI is rarely used to train teachers, unfortunately, and even if it were, the education-government complex designs school procedures and discipline rules that would make it very hard to implement.