This review presents a novel framework for evaluating evidence based on a set of parallel criteria that can be applied to both group and single-subject experimental design (SSED) studies. The authors illustrate use of this evaluation system in a systematic review of 67 articles investigating social skills interventions for preschoolers with autism spectrum disorder. Results characterize the types of treatments and research designs, the quality of studies, and effect sizes. In contrast to prior reports, this review revealed strong evidence of treatment efficacy, with group designs receiving lower ratings than SSED studies. Because this framework provides a comprehensive and transparent approach to judging the quality of studies individually and collectively, it holds promise for improving methods for identifying and implementing evidence-based practices.