The goal of the Study Design Typology is to classify any quantitative human study into one of 8 clearly defined study design types, each of which has a distinct set of biases and interpretive pitfalls that affect how evidence from these studies should be used. This typology is meant to support the critical appraisal of evidence and the classification of new and ongoing research for scientific portfolio management and analysis.
We identified the most parsimonious set of unambiguous questions about the design of any study on individual humans, that when answered, will correctly classify that study into 8 main design types (darker grey bubbles below). These design types represent distinct approaches to human investigations. Four of the design types are for Interventional studies; four are for Observational studies. The questions ask about factual features of a study's design and require little to no subjective judgement. Using our typology, a study can be classified into a main interpretive context with only 3 to 4 questions. For each main design type, '''Additional Descriptors''' (see tables below) elaborate on secondary design and analytic features that introduce or mitigate additional biases and interpretive pitfalls. As the tables show, some Additional Descriptors apply only to some design types.
Some other design typologies include those of Hartling, et al and the Cochrane Collaboration. Here are some distinguishing features of our approach and our typology:
Please note that the tables above are images, so the hyperlinks currently are not functional. Update in progress.