Outcome-Reporting Bias in Special Education Intervention Research Using Experimental and Quasi-Experimental Group Designs: A Conceptual Replication

We conducted a conceptual replication of Pigott et al.’s study of outcome-reporting bias, wherein they compared intervention outcomes reported in unpublished education dissertations with corresponding published versions. For our replication, we identified a sample of 40 special education dissertations with matched journal publications and found that statistically significant intervention outcomes from dissertations were 1.48 times more likely to be published compared with nonsignificant outcomes. Significant moderators of this effect included type of intervention outcome (academic), type of research design (randomized controlled trial), participant race (with samples greater than or equal to 50% non-White), and type of disability/exceptionality (high incidence). We found that few dissertation authors published their work, providing further evidence for the much-needed inclusion of dissertations in systematic reviews.