Education decisionmakers need access to the best evidence about the effectiveness of education interventions, including practices, products, programs, and policies. It can be difficult, time consuming, and costly to access and draw conclusions from relevant studies about the effectiveness of interventions. The What Works Clearinghouse (WWC)…

This issue of "FOCUS" discusses external validity and what rehabilitation researchers can do to help practitioners answer the question "How far can we generalize this finding-- is it applicable to other clients/patients, with different characteristics, in dissimilar settings treated by other clinicians?," which clinicians and…