When randomized control trials are not possible, quasi-experimental methods often represent the gold standard. One quasi-experimental method is difference-in-difference (DiD), which compares changes in outcomes before and after treatment across groups to estimate a causal effect. DiD researchers often use fairly exhaustive robustness checks to…

Underrepresentation of historically marginalized populations in clinical trials continues to threaten the validity of health intervention research. Evidence supports the merits of intercept and other proactive forms of recruitment for achieving more equitable representation. However, researchers also report lower retention and adherence to…

Even when raters demonstrate agreement in the use of a measure, limited score variability or violation of often-ignored statistical assumptions can result in lower reliability estimates than intuitively expected. This article uses data drawn from two randomized controlled trials of schema therapy and cognitive behavioral therapy for the treatment…

Background: Efficacy trials in education often possess a motivating theory of change: how and why should the desired improvement in outcomes occur as a consequence of the intervention? In scenarios with repeated measurements, certain subgroups may be more or less likely to manifest a treatment effect; the theory of change (TOC) provides guidance…

Educational stakeholders are keen to know the magnitude and importance of different interventions. However, the way evidence is communicated to support understanding of the effectiveness of an intervention is controversial. Typically studies in education have used the standardised mean difference as a measure of the impact of interventions. This…