Textbox: The hierarchy of scientific evidence

Abstract

Not all studies are the same. Various types of publications and articles have different scientific weight. This short summary provides an overview of the scientific evidentiary value of various types of publications with the goal to create transparency in the level of bias of any given study so that readers may, in turn, determine the attention and importance they can give the study. Practically speaking, the more bias, the less evidentiary value a study or publication has and vice versa. A figure illustrates this concept and simplifies it.