PISA data indicate that across OECD countries, students who reported that their teachers use cognitive-activation strategies in their mathematics classes also have higher mean mathematics scores. The strength of the relationship between this type of teaching and student achievement even increases after the analyses also take into account teachers' use of other teaching strategies in the students' mathematics classes. When students' exposure to cognitive activation instruction increases, their performance improves.
The use of cognitive-activation teaching strategies makes a difference no matter how difficult the mathematics problem. In fact, the odds of student success are even greater for more challenging problems. Students who are more frequently exposed to cognitive-activation teaching methods are about $10 \%$ more likely to answer easier items correctly and about $50 \%$ more likely to answer more difficult items correctly.