On the Importance of Moderator Analysis in Intervention Research: An Introduction to the Special Issue

Contributors to this special issue of Exceptional Children were supported by the National Center for Special Education Research (NCSER) in the Institute of Education Sciences. NCSER supports rigorous research on infants, toddlers, children, and youth with disabilities and at risk for disabilities through its grants program. An important purpose of this grants program is to develop new or modify existing interventions and to evaluate their efficacy and effectiveness. In 2013, NCSER invited applications for research projects to contribute to its Accelerating the Academic Achievement of Students With Learning Disabilities Research Initiative (hereafter, “A3 Initiative”). NCSER’s aim in establishing the A3 Initiative was partly to draw attention to millions of America’s children and youth who are underachieving in school (NCES, 2018). “Underachievement,” a level of performance unexplainable by one’s capacity to learn, is more prevalent and severe among students with disabilities (SWDs; e.g., Gilmour, Fuchs, & Wehby, in press; Schiller, Sanford, & Blackorby, 2008; Wagner, Newman, Cameto, Levine, & Marder, 2003). Most schools recognize that their core instruction does not help all learners. They understand, too, that “inclusive” practices, like co-teaching, have benefited few SWDs (cf. Cook, McDuffie-Landrum, Oshita, & Cook, 2011). Recognition that poorly achieving students with and without disabilities require a more appropriate education is implicit in many schools’ support of a response-to-intervention (RTI) approach, specifically, its multiple tiers of instruction that (in principle) offer the structure and opportunity to apply programs of greater intensity when those of lesser intensity prove ineffective. In a sense, the instructional tiers of RTI dovetail with NCSER’s longstanding support of researchers working to develop more intensive (Tier-2) and most intensive (Tier-3) programs in reading and mathematics. Scores of published evaluations have documented that at-risk students participating in these programs have performed statistically significantly more strongly than comparable controls. Development of such programs is no mean feat. They collectively represent a noteworthy achievement about which the research community should be proud. They should also be considered seriously for adoption by schools wishing to make RTI work for their students and teachers. Nevertheless, two caveats are in order. First, when researchers report that students in program x outperformed controls, they are saying that the treated children bested controls by an amount or degree required so that results may be considered reliable; they are not necessarily saying that program x changed the treated children’s status from “at risk” to “no longer at risk.” A second caveat more pertinent to this special issue is that none of the intensive reading 811924 ECXXXX10.1177/0014402918811924Exceptional ChildrenFuchs and Fuchs issue-article2018