Not surprisingly, nondisabled students generally outperform learning-disabled students. Importantly, however, there was less difference between the performance of the two groups when learning-disabled students were exposed to treatments that included strategy instruction compared to competing treatments like direct instruction. Only a few instructional components successfully predict effects on student achievement. This happens because individual strategies typically do not appear in isolation in a classroom, and often their importance as predictors is enhanced in the context of other components. However, single subject design studies found large effects in all subjects except for handwriting.
Treatment effects are specific to the academic problems being addressed.
If you look across academic subjects, the most effective model was a combination of direct instruction and strategy instruction. However, its effect was greater in reading than in non-reading measures, such as mathematics and social skills. Within the field of reading, this model is particularly effective for reading comprehension compared to reading recognition. For single-subject design studies, the combined model yields higher effect sizes for the lower IQ discrepancy studies when compared to those studies that report discrepancies, but with relatively higher IQ scores. Similarly, variations in how the studies were conducted can have a significant impact on treatment outcomes.