Fig. 3

Venn diagram indicating the number of studies that investigated the following questionable research practices; “Justification”—authors do not use the results of a systematic and transparent collection of earlier similar studies when justifying a new study; “Design”—authors do not use the results of a systematic and transparent collection of earlier similar studies when designing a new study; and “Context”—authors do not systematically and transparently place new results in the context of existing evidence, and any combinations thereof. Ten of the studies investigating whether authors use the results of a systematic and transparent collection of earlier similar studies when justifying a new study also evaluated whether authors of a scientific study referred to all earlier similar studies. One of the six studies in the middle section also investigated whether authors used the results of a systematic and transparent collection of the new research projects’ end user’s perspectives to inform the justification and design of the new study