Randall R. Robey's Levels of Evidence
Randall R. Robey is an associate professor and director of the Communication Disorders program in the Curry School of Education at the University of Virginia. His research combines two areas of concentration: clinical aphasiology and quanitifying valid indices of change brough about by clinical interventions.
Sources of Evidence Classifcation
Meta-analysis of multiple well-designed controlled studes 1A
Well-designed randomized controlled trials 1
Well-designed non-randomized controlled trial (quasi-experiments) 2
Observational studies with controls (restrospective studies, 3
interruped time-series studies, case-control studies, cohort studies
with controls)
Observational Studies without controls (cohort studies without controls 4
and case series)