Can I use a database filter to retrieve a publication type or population?
Answer
We don't recommend using filters for retrieving certain types of articles or articles about a specific population (children, women, elderly, etc.). This is because most medical databases rely on the indexed information. If an article has not yet undergone the indexing process, they will not show up in your list of results.
On PubMed's user guide, the warning for most filters reads as follows: "These filters may exclude some citations because they have not yet completed the MEDLINE indexing process."
PubMed also warns about the use for publications type specifically: "These filters may exclude some citations that have not yet completed the MEDLINE indexing process because they rely on the Publication Type [pt] data for the citation; publication type data may be supplied by the publisher or assigned during the MEDLINE indexing process."
A more accurate way to retrieve these types of articles is to build the concepts into the search directly. For example, if you only want to retrieve articles about children, you can build a pediatric concept into the search and combine it with the rest of your concepts. Do this by including all the relevant MeSH terms and possible keywords. Likewise, you can do this by publication type as most publication types have corresponding MeSH terms or the type of publication is directly in the title.
When conducting systematic reviews, we recommend that no filters be used, whether they are for publication type, age group, sex or species. Instead, you should be screening for articles that meet your inclusion criteria.