Missing Data Reporting and Handling in Special Education Group Intervention Research

We conducted a systematic review of missing data handling and reporting in a 1-year cross-section (2020) of group design special education intervention research. We identified 121 intervention studies. Of these 72 (60%) reported missing data at the case, variable, or item level. Few studies examined the mechanism underlying their missing data and most handled the missingness with either complete case analysis (listwise) or pairwise deletion. We discuss the implications of these findings and offer recommendations for improved reporting and handling methods.