The knowledge obtained by implementing evidence-based practice guidelines is useful for healthcare quality improvement only after patients’ health problems have been accurately diagnosed, because a correct diagnosis points to the correct guidelines to use.

While clinicians often do come up with the proper diagnoses, errors regularly occur for host of reasons.[1,2] Furthermore, even experienced clinicians sometimes unaware if the diagnoses they make are correct at the time they make them. There is a tendency for them to be overconfident, believing faulty diagnoses are valid. While diagnostic aids can help reduce errors, they should not rely exclusively on whether clinicians believe such support is needed.{[3]

One reason is for diagnostic errors is the fact that it is impossible for the unaided human mind to consider all the details and facts that required for consistently accurate diagnoses For one thing, how is it humanly possible for a clinician possibly keep up with the medical literature? For example, in 2004 the Medline medical database had 3,672 articles about adult coronary heart-disease studies. To read all the articles in this one clinical area alone would take 115 eight-hour days at 15 minutes per article. And that’s only one disease; how can clinicians retain information on some 12,000 known diseases in their heads?

Some diagnostic decision-support aids help clinicians evaluate complex cases, other take patients and providers through a thorough—and documented—question-and-answer routine at each encounter. These tools evaluate symptoms, medical history, physical findings, test results, etc. and then return a list of diagnoses for the clinician to consider. Some also include a list of care options to consider, with links to journal articles on which the recommendations are based. Such tools can improve outcomes.[4]

Research has shown that diagnostic decision-support aids can prompt physicians to consider diagnoses that they might not otherwise consider and improve diagnostic performance, especially in difficult clinical cases.[5,6,7,8]

Despite the great promise these tools hold, there needs to be greater investment in their ongoing development to optimize their usability and benefit.[9]

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Footnotes and References

[1] Weed, L.L. (2004). Shedding our illusions: a better way of medicine. Sexuality, Reproduction & Menopause; 2(1), 45-52 Available at
[2] Schiff, G.D. Diagnosing Diagnosis Errors: Lessons from a Multi-institutional Collaborative Project. AHRQ -Advances in Patient Safety; Vol 2. Available at
[3] Friedman C.P., et al. (2005). Do Physicians Know When Their Diagnoses Are Correct? Implications for Decision Support and Error Reduction. Journal of General Internal Medicine; 20 (4), 334
[4] The computer will see you now. Dec 8th 2005. The Economist Newspaper Ltd. Available at
[5] Berner, E.S., et al. (1999). Effects of a Decision Support System on Physicians' Diagnostic Performance. Journal of the American Medical Informatics Association; Sep–Oct; 6(5): 420–427. Available at
[6] McGowan, J.J. and Winstead-Fry, P. (1999). Problem Knowledge Couplers: reengineering evidence-based medicine through interdisciplinary development, decision support, and research. Bulletin of the Medical Library Association; 87(4): 462–470. Available at
[7] Ramnarayan, P. et al. (2004). A novel diagnostic aid (ISABEL): development and preliminary evaluation of clinical performance. Medinfo;11(Pt 2):1091-5. Available at
[8] Graber, M. and VanScoy D. (2003). Emergency Medicine Journal; 20 (5): 426. Available at
[9] Alper, P.R. (Sep. 2006). Are Medical Decision Support Systems Helpful? Internal Medicine World Report. Available at

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