The Influence of Measurement Error Associated With Oral Reading Progress Monitoring Measures on the Consistency and Accuracy of Nonparametric Single-Case Design Effect Size Outcomes

Researchers and practitioners frequently use curriculum-based measures of reading (CBM-R) within single-case design (SCD) frameworks to evaluate the effects of reading interventions with individual students. Effect sizes (ESs) developed specifically for SCDs are often used as a supplement to visual analysis to gauge treatment effects. The degree to which measurement error associated with academic measures like CBM-R influences said ESs has not been fully explored. We used simulation methodology to evaluate how common magnitudes of error influenced the consistency and accuracy of outcomes from two nonparametric SCD ESs, percentage of data exceeding baseline trend and TauU. After accounting for other data characteristics, measurement error accounted for a statistically and practically significant amount of variance in the consistency and accuracy of outcomes from both ESs. This article suggests that the psychometric properties of academic measures are important to consider when interpreting ESs from SCDs.