Case Studies: The Neglected Study Design in Medicine

In clinical researches, studies are categorized into two main groups: observational and interventional. In a general division, observational studies are also divided into descriptive and analytical studies. Case-control, cohort and cross-sectional studies are the three famous study designs in the descriptive category. Case studies which include case reports and case series are also in this category. Although these two types of studies provide weak evidence for causal relationship based on evidence hierarchy, but they have specific advantages, leading to being used by researchers in certain cases. The goal of this study is to review some important points in writing a manuscript with these study designs.