IQ Is Not Strongly Related to Response to Reading Instruction: A Meta-Analytic Interpretation.

A meta-analysis of 22 studies evaluating the relation of different assessments of IQ and intervention response did not support the hypothesis that IQ is an important predictor of response to instruction. We found an R(2) of .03 in models with IQ and the autoregressor as predictors and a unique lower estimated R(2) of .006 and a higher estimated R(2) of .013 in models with IQ, the autoregressor, and additional covariates as predictors. There was no evidence that these aggregated effect sizes were moderated by variables such as the type of IQ measure, outcome, age, or intervention. In simulations of the capacity of variables with effect sizes of .03 and .001 for predicting response to intervention, we found little evidence of practical significance.