Built in filters

Some database interfaces include an option to apply a filter to search results without the need to manually key in the search filter. The development of the filter is often described and published separately in peer reviewed publications. 

PubMed, Ovid Embase and Ovid MEDLINE all have the option to limit to 'Clinical Queries'. Using this feature allows the searcher to restrict their search results to one of the following: 

therapy, diagnosis, prognosis, causation (etiology), clinical prediction guides, qualitative, economics, and cost. 

Within these categories it is also possible to select whether sensitivity, specificity or a balance of these two factors is required. More information about these “Clinical Queries” search filters is available

Another built in filter available in PubMed, Ovid Embase and Ovid MEDLINE is the Systematic Reviews filter. In PubMed this can be applied via Clinical Queries, Article Types or by adding systematic [sb] to the search query. More information about the coverage of this filter is available.  In the Ovid databases it can be applied via selecting Additional limits and then Clinical Queries

PubMed also includes a range of Medical Genetics search filters that can be applied to search results. These include filters for diagnosis, differential diagnosis, clinical description, management and testing. More information about these and their development is available. 

Superfilters service from McMaster University is aimed at clinicians and provides a simultaneous search of pre-appraised clinical literature from the McMaster Premium Literature Service (McMaster PLUSTM) and PubMed, incorporating a wide selection of search filters including:  therapy, diagnosis, prognosis, clinical prediction guides, economics, etiology for harm, quality improvement, knowledge translation, qualitative studies, appropriateness, process assessment, outcome assessment, costs and review. The searcher can select a specific, balanced or sensitive approach to suit their requirements. Registration required but subsequently free to use

There are other automated filters which are offered as standalone tools.  One example is RCT Tagger.  In this resource a subject search is entered into a search line and the search is run against PubMed.  The results returned are presented in order of probability of the record being a report of an RCT according to the underlying algorithm. The development of the filter is presented in a supporting paper.