Evidence Syntheses (Scoping, systematic, & other types of reviews)

Evidence syntheses range from being highly systematic in approach with formal published guidelines to follow, to methodologies with fewer defined requirements. No matter what methodology best matches your project, you can still be structured in approach and produce a robust review. Think through the criteria below, then visit the Types of Reviews page to explore a methodology that meets your needs.

Project Goal

• Produce a published evidence synthesis paper
• Support a grant application or project
• Class/course assignment
• Find information to support a primary study

Resources: Time & Team

• Team of 2+ OR single author?
• Experience with evidence synthesis OR new to evidence synthesis?
• >12 months to completion OR <6 months to completion?
• Dedicated research time OR In addition to regular duties?

Question Type

• "What is the effectiveness of …" Focused, specific clinical question
• "What's out there on…" Broad, exploratory question
• “We need to quickly summarize the evidence on...” Emerging topics

Available Literature

• Large number of rigorous primary studies
• Heterogeneous study designs
• Scarce literature 

The figure¹ below gives a high-level overview of the stages of the meta-analysis process. Related evidence synthesis methods may omit steps in the meta-analysis process; for example, systematic reviews will not include Step 14 meta-analyze.

Note the iterative nature of the process as search updates are conducted later in the project at Step 13 (an arrow on the left connects to Step 6 de-duplicate).

While this figure highlights appraisal of relevance in Steps 7 (screen abstracts) and 9 (screen full text), guidelines recommend critical appraisal of the individual study's validity and results once it is selected for inclusion.

¹Tsafnet, G., Glasziou, P., Choong, M.K., et al. Systematic review automation technologies. Systematic Reviews 2014; 3:74;  http://www.systematicreviewsjournal.com/content/3/1/74. (adaptation of original image)