Systematic Reviews and other evidence synthesis projects

The PRISMA Statement: Preferred Reporting Items for Systematic Reviews and Meta-Analyses
Evidence-based minimum set of items for reporting in systematic reviews and meta-analyses.  Focused on randomized trials,  PRISMA can also be used as a basis for reporting systematic reviews of other types of research, particularly evaluations of interventions.

The PRISMA flow diagram is a tool for recording and reporting the number of records during the different steps of a systematic review, along with reasons for exclusion. It is often included within the review or as supplemental material.

Tool for Generating a PRISMA Search Flow Diagram - from the Evidence Synthesis Hackathon

Complying with PRISMA and Standards for Cochrane: See Cochrane Handbook > Methodological Expectations of Cochrane Intervention Reviews (MECIR)

Document Your Search Strategies

• Save your exact search strategy for each database in a text document.
• Record date each database searched, years covered, and number of hits retrieved.
• Record number of hits after de-duplication against other database results.

Tip: Save your search string for future use in personal account within each database (eg MyNCBI in PubMed, My Saved Searches in Web of Science, My EBSCOhost in CINAHL Plus).

Write Up Search Methods

PRISMA for Searching: comprehensive guidance on how to report your search methods, including a checklist and full explanatory paper.

See Appendix 3: Documenting the Search Process in Systematic Reviews: CRD's guidance for undertaking reviews in health care. Centre for Reviews and Dissemination. January 2009.

Searching for and Selecting Studies chapter of the Cochrane Handbook.

For additional models of search methodology reporting, refer to see other guidelines in Guides for Conducting Systematic Reviews.

Manage Your Search Results

Export the results of your search from each database. For instructions, see the guide for your database in the Database Searching guides or check the Help or Support for the database.

Import the file into your citation management tool. For instructions, see Citation Management Tools for guides on using EndNote, EndNote Web and other citation management programs for importing, and for storing and organizing search results.

De-duplicating

In your searches across multiple databases, there will be some articles that are retrieved in more than one database. This is expected, but you don't need to evaluate that article more than once. Before you start screening, de-duplicate. The processes described below are methods for removing duplicates while minimizing the risk of accidentally removing similar non-duplicate articles.

SRA-DM tool:  Rathbone J, Carter M, Hoffmann T, Glasziou P.  Better duplicate detection for systematic reviewers: evaluation of Systematic Review Assistant-Deduplication Module. Syst Rev. 2015 Jan 14;4:6. doi: 10.1186/2046-4053-4-6. PubMed PMID: 25588387.

For desktop version of EndNote only: Bramer WM, Giustini D, de Jonge GB, Holland L, Bekhuis T. De-duplication of database search results for systematic reviews in EndNote. Journal of the Medical Library Association : JMLA. 2016;104(3):240-243. doi:10.3163/1536-5050.104.3.014<

Make a note of how many duplicates were removed for reporting in your paper. Your PRISMA flow diagram is a good place to keep track.

Steps for screening

The purpose of article screening to remove studies that are not eligible for inclusion.

Review support software will typically include a record screening/study selection function. This allows more than one reviewer to independently screen the records without seeing other reviewers' decisions to include or exclude studies, and thus reducing bias. Areas of disagreement can be resolved by consensus or by a third party who is an expert in the field.

Use your inclusion/exclusion criteria to conduct the following.

1. Title/abstract screening: First, screen the title and abstracts of the studies and determine whether they are relevant to your research question. Since you conducted a comprehensive search, there will be items that were captured that are clearly not relevant.
2. Full text screening: For studies included based on the title/abstract screening, obtain the full text and evaluate for inclusion/exclusion.

During both steps, record your reason for excluding an item. Review support software commonly contains features to simplify this.

Project management software for systematic reviews and other evidence synthesis:

These tools provide support for independent screening of the title/abstracts and the full text of articles. Some have additional features, such as support for data extraction or machine-learning to sort results. Additional tools are described in the Wu et al. poster below.

Chart showing the features of different tools and which step during which they are relevant:
"Digital Tools for Managing Different Steps of the Systematic Review Process". Wu W, Akers K, Hu E, Sarkozy A, Vinson P. Library Scholarly Publications. 2018; 136. https://digitalcommons.wayne.edu/libsp/136

Reviewing retrieved references for inclusion in systematic reviews using Endnote. Bramer WM, Milic J, Mast F. J Med Libr Assoc. 2017 Jan; 105(1): 84-87.

Reference checking for systematic reviews using Endnote. Bramer WM. J Med Libr Assoc. 2018 Oct; 106(4): 542-6.

Covidence and Rayyan. Kellermeyer L, Harnke B, Knight S. J Med Libr Assoc. 2018 Oct; 106(4): 580-3. (Review)