Social validity in single-case research: A systematic literature review of prevalence and application

Background: Single-case research (SCR) has been a valuable methodology in special education research. Montrose Wolf (1978), an early pioneer in single-case methodology, coined the term social validity to refer to the social importance of the goals selected, the acceptability of procedures employed, and the effectiveness of the outcomes produced in applied investigations. Since 1978, many contributors to SCR have included social validity as a feature of their articles and several authors have examined the prevalence and role of social validity in SCR. Aim and methods: We systematically reviewed all SCR published in six highly-ranked special education journals from 2005 to 2016 to establish the prevalence of social validity assessments and to evaluate their scientific rigor. Results: We found relatively low, but stable prevalence with only 28 publications addressing all three factors of the social validity construct (i.e., goals, procedures, outcomes). We conducted an in-depth analysis of the scientific rigor of these 28 publications. Conclusions: Social validity remains an understudied construct in SCR, and the scientific rigor of social validity assessments is often lacking. Implications and future directions are discussed.