Comparison of dual discrepancy criteria to assess response to intervention

Much of the research regarding diagnosing children as LD with responsiveness-to-intervention (RTI) has examined methods to identify children as non-responsive. The current study examined the dual discrepancy (DD) definition in which children score low on a post-intervention reading measure and score below their peers in reading growth rates. Four definitions of DD were compared, student growth below the 25th percentile, 33rd percentile, 50th percentile, and less than one standard deviation below the mean. Participants were 151 children in grades 1 through 3 who were identified as experiencing reading difficulties. Results suggested that the three percentile groups significantly differentiated reading scores between DD and non-DD children, but the one standard deviation group did not. No ethnic or gender biases were noted and the 25th and 33rd percentile criteria closely matched estimates of LD prevalence. Implications for future research are included.