In this section: Citing databases and study registers | Search terms

Citing databases and study registers

The preferred format for the following databases is all upper-case letters: MEDLINE, CENTRAL, OLDMEDLINE, and CINAHL (not CINHAL). A number of databases use a mixture of lower-case and upper-case letters, for example, Embase (not EMBASE), PsycLIT (not PsychLIT) and PsycINFO (not PsychINFO).

Some Cochrane Review Groups maintain a register of studies in their area of expertise. The name of the register may vary, but it will follow one of the following formats depending on the Cochrane Review Group’s choice: [Cochrane Group name] Specialized Register; [Cochrane Group name] Specialised Register; or [Cochrane Group name] Trials Register.

The databases and trials registers and other resources that are searched for studies for a Cochrane review are listed in the ‘Search methods for identification of studies’ (in the Methods section). The databases and registers must be listed in the following order: [Cochrane Group name] Specialised Register (or Specialized Register or Trials Register), CENTRAL, MEDLINE, Embase, and any other databases.

In the Abstract, brief text may be used to describe the sources searched, e.g. ‘We used CENTRAL, MEDLINE, xx other databases and xx trials registers, together with reference checking, citation searching and contact with study authors to identify studies that are included in the review. The latest search date was x/xx.' (Add key limitations, if present).

In the Search Methods section, the date of the latest search (day month year) should be provided along with the issue or version number (as appropriate) of each database, e.g. CENTRAL (year, issue number). The date of inception of the database should be given where known. Database names should include the platform or provider name, and websites should include the full name and URL.

The date range (for databases) or search date (for study registers) of each search must be listed with each database; for example, CENTRAL (year, issue number), and for most other databases, such as MEDLINE, it should be in the form 'MEDLINE (year to day month year)'.

Example:

• Cochrane Wounds Specialized Register (searched 10 February 2023);
• Cochrane Central Register of Controlled Trials (CENTRAL; 2023, Issue 1) in the Cochrane Library (searched 10 February 2023);
• MEDLINE Ovid (1946 to 10 February 2023);
• Embase Ovid (1974 to 9 February 2023);
• CINAHL EBSCO (Cumulative Index to Nursing and Allied Health Literature; 1982 to 9 February 2023);
• PsycINFO Ovid (from 1806 to 10 February 2023);
• AMED Ovid (Allied and Complementary Medicine; 1985 to 10 February 2023);
• LILACS (Latin American and Caribbean Health Science Information database; 1982 to 10 February 2023);
• ISRCTN registry (www.isrctn.com; searched 10 February 2023); 
• US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (www.clinicaltrials.gov; searched 10 February 2023);
• Australian New Zealand Clinical Trials Registry (www.anzctr.org.au; searched 10 February 2023);
• World Health Organization International Clinical Trials Registry Platform (apps.who.int/trialsearch; searched 10 February 2023);
• EU Clinical Trials Register (www.clinicaltrialsregister.eu; searched 10 February 2023).

Other formatting options for MEDLINE and Embase:

• MEDLINE Ovid (1946 to November week 3 2023)
• Embase Ovid (1974 to 2023 week 47)

Search terms

Search terms consist of text words (preferred spelling is two words, not 'textword') and indexing or controlled vocabulary terms. The preferred format for referring to the National Library of Medicine's controlled vocabulary used for indexing articles for MEDLINE (and PubMed) is MeSH (not MESH).

Focused review format: supplementary materials

The full line-by-line search strategies for each database (and other sources, if applicable) with search strings, database names, access platforms, search fields and other limitations/settings should be included in the Search strategy supplementary material (supplementary material 1).