Table 1 Differences between a systematic map and systematic review

Objective

Describes the state of knowledge for a question or topic

Aims to answer questions with a quantitative or qualitative answer

Question formulation

Question can be open-framed or closed-framed. Topic can be broad or narrow

Question is usually closed-framed

Search strategy

No limitation on research evidence that can be included (e.g. primary and secondary research)

Evidence is limited to primary qualitative or quantitative research. For example comparative, prevalence or occurrence type studies

Article screening

Articles not obtainable at full text (where the full document is not available) or studies with limited data may be included

Article full text is usually required to extract relevant data

Data extraction

Information describing the study and its methods are extracted. Study results may not be extracted

Information describing the study and its methods and studies’ qualitative and or quantitative results extracted

Critical appraisal

Critical appraisal optional

All included studies critically appraised for study internal and external validity

Synthesis

Trends in the literature, knowledge gaps and clusters identified but no ‘synthesis of study results’ carried out

Qualitative or quantitative synthesis of study results where possible using appropriate methodology (e.g. meta-analysis). Knowledge gaps identified

Report

Describes and catalogues available evidence relating to a topic of interest, identifying knowledge gaps and knowledge clusters. Implications for policy, practice and research made

Narrative and qualitative or quantitative synthesis study results (e.g. meta-analysis) to answer the question (where feasible). Implications for policy and practice, and identification of knowledge gaps for future research