Gibson D. Lewis Library Libguides
The evidence pyramid, also known as the hierarchy of evidence, helps visualize the various levels of research evidence in healthcare. At the base, are more basic study designs, while higher up the pyramid are greater quality studies that have undergone rigorous testing for effectiveness. As you move up the pyramid, the amount of available information decreases, but its quality and relevance to clinical practice increases. This pyramid structure provides researchers and clinicians a clear guide for selecting the best evidence to inform decisions about patient care.
At the bottom of the pyramid are animal and laboratory studies. While they provide valuable information, they are the lowest quality of evidence because their findings may not apply to humans. Moving up, case series and case reports focus on individual patients or small groups. Next, cross-sectional studies offer a snapshot of data at a single point in time, without proving cause and effect. Case-control studies compare individuals with a specific condition to those without it, identifying potential risk factors. Next, cohort studies track groups over time to see how exposures affect health. Above that are randomized controlled trials (RCTs), which randomly assign treatments and are among the most reliable forms of evidence. Finally, at the top are meta-analyses and systematic reviews, which combine results from multiple studies to provide comprehensive insights.