1.2 Select the best study design
Select the best study design to answer your question
Another essential component that must be considered in the search and selection of studies is the type of design that responds best to your question, as the following table summarizes.
Reflection
If you are able to find updated systematic reviews of good quality (about treatment, diagnostic, prognostic or otherwise) that respond to a particular clinical question, it may not be necessary to find individual original studies.