Depending on the source that you are using, RCTs and CCTS can be identified in a number of ways. For example, if you are searching MEDLINE:

• RCTs are assigned the Publication Type 'Randomised Controlled Trial';
• CCTs are assigned the Publication Type 'Controlled Clinical Trial' (but check to ensure that the CCT label matches the Cochrane criteria for a CCT).

More information

There is a Training manual for handsearchers, hosted by the Cochrane Information Retrieval Methods Group. This guide was produced in 2002, but the content is still current.