This chapter shows how to conduct a comprehensive, objective and reproducible search for studies. It is always necessary to strike a balance between comprehensiveness and precision when developing a search strategy. Developing a search strategy is an iterative process in which the terms that are used are modified, based on what has already been retrieved. An electronic search strategy should generally have three sets of terms: terms to search for the health condition of interest; terms to search for the intervention(s) evaluated and terms to search for the types of study design to be included. Searches of electronic databases are generally the easiest and least time-consuming way to identify an initial set of relevant reports. The chapter discusses how and where the reviewers should look for studies that may be eligible for inclusion such as The Cochrane Library, MEDLINE, EMBASE and other relevant databases that identify appropriate MeSH terms.

This chapter focuses on systematic reviews of injury studies and discusses the structured process of reviews that involve several steps. A well focused question allows clear decisions to be made about what research to include in the systematic review and how to summarize it. The most commonly used sources are electronic bibliographic databases. Consultation with an experienced librarian helps to identify electronic databases likely to contain citations relevant to the specific research questions. Once identified, studies must be assessed to determine whether they meet inclusion criteria. Titles, abstracts, and keywords may be sufficient to exclude many studies. The chapter explains why a systematic review is done. It presents a meta-analysis of randomized controlled trials of the effect of albumin supplementation on mortality in critically ill and injured patients. Protocols for systematic reviews and completed reviews are peer reviewed and published in the Cochrane Library.