Research and Statistics: Validity Hierarchy for Study Design and Study Type

Abstract

1. Carisa Perry-Parrish, PhD* 2. Rachel Dodge, MD, MPH† 1. *Division of General Pediatrics and Adolescent Medicine, Johns Hopkins University School of Medicine, Baltimore, Md 2. †Medical Director for Foster Care, The MATCH Program, Baltimore HealthCare Access, Inc, Baltimore, Md Identifying and implementing effective, evidenced-based care is considered best practice in pediatrics. An evidence-based clinician reviews the current literature to understand the evidence before addressing the concerns of parents such as those in the case studies, but it is important to determine what counts as good evidence. Engaging in evidence-based practice requires the clinician to interpret the evidence from research studies. Research study design and type are important considerations when determining if the conclusions of the study are valid and to provide sufficient evidence to guide clinical decisions. Both study design and type influence the validity of the research study. Validity hierarchy is based on the internal validity of the study design and type (Table). Internal validity reflects the accuracy of the study's conclusions and is needed to determine causal relations among variables; external validity reflects how well a study represents the “real world.” Different study designs (eg, experimental versus nonexperimental) and study types (eg, …