Table 2

Gough’s Weight of Evidence (WoE) criteria*26

WoE AThis is a generic and thus non-review-specific judgement about the coherence and integrity of the evidence in its own terms. That may be the generally accepted criteria for evaluating the quality of this type of evidence by those who generally use and produce it.
WoE BThis is a review-specific judgement about the appropriateness of that form of evidence for answering the review question, that is the fitness for purpose of that form of evidence. For example, the relevance of certain research designs such as experimental studies for answering questions about process.
WoE CThis is a review-specific judgement about the relevance of the focus of the evidence for the review question. For example, a research study may not have the type of sample, the type of evidence gathering or analysis that is central to the review question or it may not have been undertaken in an appropriate context from which results can be generalised to answer the review question. There may also be issues of propriety of how the research was undertaken such as the ethics of the research that could impact on its inclusion and interpretation in a review (Pawson et al 2003).
WoE DWoE A, B and C are combined to form an overall assessment WoE D of the extent that a study contributes evidence to answering a review question.
  • *Reprinted with permission from Routledge, original copyright 2007.