Improving the use of evidence in health impact assessment.

OBJECTIVE: Health impact assessment (HIA) has been proposed as one mechanism that can inform decision-making by public policy-makers. However, HIA methodology has been criticized for a lack of rigour in its use of evidence. The aim of this work was to formulate, develop and test a practical guide to reviewing publicly available evidence for use in HIA. The term evidence includes all scientific assessments, whether research studies in peer-reviewed journals or previous HIAs. METHODS: The formulation and development of the guide involved substantial background research, qualitative research with the target audience, substantial consultations with potential users and other stakeholders, a pilot study to explore content, format and usability, and peer review. Finally, the guide was tested in practice by invited volunteers who used it to appraise existing HIA evidence reviews. FINDINGS: During development, a wealth of data was generated on how the guide might be applied in practice, on terminology, on ensuring clarity of the text and on additional resources needed. The final guide provides advice on reviewing quantitative and qualitative research in plain language and is suitable for those working in public health but who may not have experience in reviewing evidence. During testing, it enabled users to discriminate between satisfactory and unsatisfactory evidence reviews. By late 2009, 1700 printed and 2500 downloaded copies of the guide had been distributed. CONCLUSION: Substantive and iterative consultation, though time-consuming, was pivotal to producing a simple, systematic and accessible guide to reviewing publicly available research evidence for use in HIA.