Q. Why should I use controlled vocabulary/subject headings and keywords when systematically searching?

Subject headings/controlled vocabulary are standardized terms that are assigned to articles when they are added to a database. This process is called indexing. By using controlled vocabulary, you can find articles on your concept even if the researchers used different terminology to refer to it (heart attack vs. myocardial infarction).

However, the indexing process isn’t perfect. Indexing takes time so brand new articles may not have controlled vocabulary assigned to them yet. Indexing also is a subjective process so the indexer may not include a term that you might use to search for the concept. This is why it is important to also use keywords when searching. Using keywords makes sure that you find any articles that may not have been indexed or may be appropriate despite missing controlled vocabulary you are using.

Each database has a different controlled vocabulary.