Twenty‐three single‐subject studies aimed at improving the writing achievement of students identified as having a learning disability were analyzed meta‐analytically. The effect size phi was used to compare the writing strategies. The dependent measures used to assess the efficacy of the interventions were also coded and reviewed. Results suggest intervention studies using the self‐regulated strategy development (SRSD) or a non‐SRSD writing strategy produced high effect sizes, suggesting the overall success of the writing interventions. Findings also indicate the 23 studies used a total of 39 dependent measures, which show the way writing achievement is measured varies greatly. Furthermore, many of the dependent measures were not standardized or technically sound.