Finding Evidence-Based Information

Finding Evidence-Based Information: Hierarchy of Resources
by Clista Clanton

Success in delivering evidence-based health care relies heavily on the ready availability of current best evidence about diagnosis, treatment, and prevention options for health disorders, ideally tailored to the characteristics and context of the individual patient or population and the resources of the provider.”1

Finding evidence-based information for patient care decisions can be a daunting task to even the most experienced searcher. The Biomedical Library has 35 different databases and information sources listed on its “Database” web page, and these are not all that are available, but rather the ones most used by our students, faculty and staff. While each database has its own unique set of strengths depending on your information need, a useful system for finding evidence-based information has been proposed in the “5S” model developed by Brian Haynes of McMaster University.

The 5S Model: When searching for information, this model suggests starting at the highest level of resources available to you. Since the University’s health system does not currently have patient electronic medical records with built-in decision support systems, the “Summaries” category would be the starting point. Biomedical Library resources that fit into this category include Dynamed, ACP Pier, and Clinical Evidence. These resources provide regularly updated summaries that integrate evidence-based information for specific clinical problems. Additionally, the review process used to compile the summary should be explicitly stated. Also included in this category would be evidence-based clinical guidelines such as those found in the National Guideline Clearinghouse.

If a summary does not exist for the condition or clinical problem you need, then the next level of information sources would be “Synopses”. These resources provide critically appraised abstracts of summaries or single studies and usually discuss the clinical applicability of the study findings. Library resources in this category include the ACP Journal Club, Evidence-Based Nursing, Evidence-Based Child Health, Evidence-Based Mental Health, DARE (Database of Abstracts of Reviews of Effect) and federated search engines such as TRIP (Turning Research into Practice).

If the information needed cannot be found in either the Summaries or Synopses levels, then the next line of resources are known as “Syntheses”. These are systematic reviews such as the Cochrane reviews. Other compilers of or sources for finding systematic reviews are the Joanna Briggs Institute, Clinical Evidence, PubMed, CINAHL, and TRIP.

At the very bottom of the 5S pyramid are the individual studies which are indexed in databases such as PubMed and CINAHL; this is not a reflection on the importance of these databases, but more so a reflection on the other information resources found higher up in the pyramid that provide value added services by having already located, synthesized and critically appraised the best available evidence they deliver. Databases such as PubMed and CINAHL continue to provide the very important function of powerful search engines that access the abstracts of the vast amount of the health science journal literature; yet when using these two resources, it is still up to the searcher to locate, synthesize, and critically appraise the information they find, thus making these a lower form of information sources.

As is the nature of pyramids (narrow at the top and broad at the bottom), information sources at the higher levels may not provide coverage of the clinical problem you are addressing, making it necessary to look at the lower, yet more comprehensive in coverage, levels. However, starting with the higher levels can yield great payoffs in terms of time saved and confidence in the information found, making them the best place to start in your search.

The 5S model is evolving, and the September 2009 edition of ACP Journal will include an editorial by Brian Haynes discussing fine-tuning the 5S model into a 6S Model.

1 Haynes, RB. Of studies, summaries, synopses, and systems: the “5S” evolution of information services for evidence-based healthcare decisions. ACP J Club 2006;145:A-8.

From the Fall 2009 issue of the Biofeedback Newsletter.