Conducting a literature review on the effectiveness of health care interventions.

The dramatic increase in the volume of research based information means that effective policy makers must be able to conduct and interpret literature reviews. This article sets out the steps that should be followed in doing so. They are: explicitly defining the question; locating relevant literature; assessing the quality of studies and deciding whether they should be included; synthesizing and re-analyzing the results; and presenting them in a clear and concise manner. The article identifies the leading sources of information, including electronic databases and useful Internet addresses and describes briefly how each stage should be conducted, highlighting the strengths and weaknesses of different approaches and the ways in which bias may be introduced.