Empirical benchmarks for between-case standardized mean differences from single-case multiple baseline designs examining academic interventions.

The between-case standardized mean difference (BC-SMD) is an effect size measure for single-case designs (SCDs) that it puts findings on the same scale as standardized mean differences for between-group designs. Although the BC-SMD is being applied in practice, the field still lacks guidelines for interpreting its magnitude. We develop empirical benchmarks for BC-SMDs from multiple baseline and multiple probe SCDs examining academic interventions. Drawing on a large corpus of SCDs identified using a systematic search process, we develop benchmarks for multiple baseline and multiple probe designs that examine the effects of math, reading, and writing-related interventions for students in school settings. We find distributions of effect sizes that are broader and more dispersed than distributions observed in group designs.