In experimental research, internal validity refers to what extent researchers can conclude that changes in dependent variable (i.e. outcome) are caused by manipulations in independent variable. The causal inference permits researchers to meaningfully interpret research results. This article discusses (a) internal validity threats in social and…

Increased accountability in education has resulted in a focus on implementing interventions with strong empirical support. Both student outcome and treatment integrity data are needed to draw valid conclusions about intervention effectiveness. Reviews of the literature in other fields (e.g., applied behavior analysis, prevention science) suggest…