ABSTRACT
A systematic literature search will counteract skewness by the selection of studies, so that researchers end up with something better than a map of the research literature that merely confirms their own ideas of what is important. A. Booth presents three criteria for an effective search strategy: it retrieves relevant records, it does not retrieve irrelevant references and the search terms as a whole are parsimonious to avoid redundancy. The classic version of the systematic review was developed in the evidence-based medicine tradition to answer questions about which interventions are working and to contribute to improving the bases for decision-making in health care. The majority of the research literature in medicine and the health sciences is written in English and therefore is readable by researchers in most high-income countries. Several of the research literature databases do, however, include articles written in languages other than English, often with an abstract in English.
