Early intervention for children at risk for reading disabilities: The impact of grade at intervention and individual differences on intervention outcomes.

Across multiple schools in three sites, the impact of grade-at-intervention was evaluated for children at risk or meeting criteria for reading disabilities. A multiple-component reading intervention with demonstrated efficacy was offered to small groups of children in 1, 2, or 3 grade. In a quasi-experimental design, 172 children received the Triple-Focus Program (PHAST + RAVE-O), and 47 were control participants. Change during intervention and 1-3 years later (6-8 testing points), and the influence of individual differences in predicting outcomes, were assessed using reading and reading-related repeated measures. Intervention children out-performed control children at posttest on all 14 outcomes, with average effect sizes (Cohen's ) on standardized measures of .80 and on experimental measures of 1.69. On foundational word reading skills (standardized measures), children who received intervention earlier, in 1 and 2 grade, made gains relative to controls almost twice that of children receiving intervention in 3 grade. At follow-up, the advantage of 1 grade intervention was even clearer: First graders continued to grow at faster rates over the follow-up years than 2 graders on six of eight key reading outcomes. For some outcomes with metalinguistic demands beyond the phonological, however, a posttest advantage was revealed for 2 grade Triple participants and for 3 grade Triple participants relative to controls. Estimated IQ predicted growth during intervention on seven of eight outcomes. Growth during follow-up was predicted by vocabulary and visual sequential memory. These findings provide evidence on the importance of early intensive evidence-based intervention for reading problems in the primary grades.