How many databases should I be searching when conducting a knowledge synthesis?
Answer
There is no optimal number of databases you must search in when conducting a systematic review. Different databases index different journals. This is why it is important to look in more than one database.
For example, if your knowledge synthesis has to do with bariatric surgery and you conduct a search in Medline and Embase only, you will be missing potentially relevant articles that are published in the journal Bariatric Nursing and Surgical Patient Care, as this journal is indexed in CINAHL, or in Obesity Surgery, as this is indexed in Web of Science.
A research study by Bramer et al. published in 2017 suggests the use of Medline, Embase, Web of Science and Google Scholar as the most favourable combination for searching. However, it is important to consider the scope of your project and the question at hand. Other databases may also be necessary to get a complete set of results.
Speak to your librarian about the nature of your project and the databases that will work for you.