Searching Best Practices for Evidence Synthesis Reviews

Field codes tell the database where to search for a term in a record. For example, using the author field code will tell the database to only search for your term in the author field. The title field code will only search for your term in the title field. 

If you don’t assign a field code, databases will usually search for a term in many different places within the article record: title, abstract, journal name, etc. Each database can vary slightly in what fields they will search if no field code is indicated. This is a problem when your goal is to replicate a search as closely as possible in multiple databases. By using field codes and understanding what field codes are doing in each database, you will be able to construct as close to the same search as possible for each database. (See Translate Your Search page)

Common ones that are used in systematic searches are:

• the subject heading ([Mesh] in PubMed)
• text word ([tw] in PubMed, which will search mostly everything in a record)
• Title/Abstract ([tiab] in PubMed, which will search for the term in the record’s title and abstract).

Field codes can be found in each database’s respective help pages. The Boxer Library also has a Database Syntax Comparison Chart for popular databases that can get you started.