A typology of systematic reviews for synthesising evidence on health care.

There are six types of systematic reviews: narrative; meta-analysis; scoping; qualitative; umbrella; and realist. Each type has distinct objectives, characteristics and attributes, but with much overlapping of methods and guides. Sensitivity to the need for qualitative evidence on complex human responses to ill-health and health care has broadened the objectives and methods of health-related systematic reviews to find, appraise and synthesis useful evidence for practice guidelines, healthcare policy and allocation of health resources.