Hierarchy of research design used to categorize the "strength of evidence" in answering clinical dental questions.

The purpose of this article is to highlight important features of research design that clinicians can use to determine which articles are useful when attempting to answer clinical questions and determine the best therapy for a particular patient. This article offers a systematic means of categorizing the quality of research reports for clinicians and clinical investigators. A recurring clinical theme of hygiene education is used to exemplify how phrasing the clinical question determines the type of study design that could be used. The article describes the continuum of research reports, and categorizes them by their inherent strengths and weaknesses. The report describes why the research designs in the supreme position of the research hierarchy, are the most valuable to clinicians seeking evidence that defines the best therapy for their patients.