Faculty of Health and Medical Sciences

Appraise the evidence

Validity

A set of scales for weighing things

A valid piece of research truly measures what it sets out to measure.

To give valid results, a piece of research needs to:

  • have clear objectives
  • include methodology to minimise bias
  • draw the appropriate conclusions from the data

These questions can be asked of all levels of evidence and all types of questions, and are equally important for systematic reviews or guidelines.

Does the introduction clearly describe the objectives of the study?
  • Did the researchers know what they were trying to study from the outset?
  • Is the focus of the report in keeping with the study objectives?
Has the risk of bias been minimised in the study methodology, study reporting, and patient selection?
Do the authors draw conclusions that are supported by the data?

Conclusions in the abstract and discussion may be biased by the author’s pre-determined ideas about the results.

You should ensure that the results and the conclusions are concordant. Have the authors discussed other work that both supports and contradicts their findings or have they focused on one aspect only?