Introduction

The readers of our journal most likely have busy clinical, administrative and/or teaching roles. As such, time is of the essence when thinking about answering clinical questions that arise in patient care. DiCenso and colleagues recently published a hierarchy of pre-appraised evidence called the 6S model.1 This model denotes in a pyramidal fashion the six levels of evidence available in clinical decision making. It starts with the largest resource available at the base of the pyramid with individual original studies. It then moves upward through synopses of studies, syntheses, synopses of syntheses, summaries and ends with the most specific form of evidence at the apex, with the “systems” layer. This article is a primer on how to use the 6S model when searching for and assessing the highest quality of evidence. The text and Table provide a summary view of clinical questions associated with each stage of the hierarchy, the strengths and weaknesses …