"Evidence-based medicine…is the conscientious, explicit and judicious use of current best evidence in making decisio
ns about the care of individual patients. The practice of evidence-based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research." (Sackett, 1997)
Evidence-based practice has become increasingly important in the fields of medicine. An evidence-based practice is a treatment methodology or procedure that has been tested, studied, and proven effective--not just accepted blindly as a standard practice. The process of systematically finding, appraising, and using contemporaneous research findings as the basis for clinical decisions. Evidence-based medicine (EBM) follows four steps: formulate a clear clinical questions from a patient's problem; search the literature for relevant clinical articles; evaluate (critically appraise) the evidence for its validity and usefulness; implement useful findings in clinical practice. Rosenberg W, Donald A. Evidence based medicine: An approach to clinical problem-solving. BMJ. 1995;310:1122-1126This section of the Libguide will help you to understand the steps of implementing evidence-based practice and for finding pertinent articles and research.
Step 1: Assess your patient and determine the pertinent issues. You may be looking for evidence about therapy options, prognosis or diagnostic techniques.
Step 2: Ask a clinical question. Use the PICO model to formulate a clear and concise clinical question.
Step 3: Acquire the best evidence. Search the appropriate databases and resources to find the best evidence.
Step 4: Appraise the evidence. Determine whether the information you found is relevant, valid and applicable to your patient.
Step 5: Apply the evidence to your patient. Ensure that the evidence and recommendations meet your patient's values and expectations.
In the age of open-access publishing, it is easier than ever to have a journal article published. It isn't always clear if the article went through the peer review process, so it is important for you to take a critical look at the information you find in an article. Here are some criteria to consider applying to articles.
Authority – what are the qualifications of the authors? Was the article published in a reputable journal?
Accuracy – is the information reproducible or cited by other sources? Are references cited throughout the article?
Bias – does the author have a conflict of interest? PubMed now includes conflict of interest statements when this information is supplied by the publisher.
Currency – when was the article published? Is the information out of date for your purposes?
Comprehension – is the information written at an appropriate level for its audience? How does the information compare with other sources on this topic? Is the article relevant to your research?
Although textbooks may go through a peer review and editing process, it is still important for you to take a critical look at the information you find in a textbook. Here are some criteria to consider applying to websites.
Authority – what are the qualifications of the authors and/or editors?
Accuracy – is the information reproducible or cited by other sources? Are references cited throughout the book?
Bias – does the author or editor have a conflict of interest?
Currency – when was the book published? Are there newer editions? Is the information out of date for your purposes?
Comprehension – is the information written at an appropriate level for its audience? How does the information compare with other sources on this topic? Is the textbook well organized and easy to follow?
The ABC's of evaluating websites
There is no quality control or peer review on the Internet. Therefore, it is important that Internet users are able to critically appraise the quality of the information they come across. Here are some criteria to consider applying to websites.
Authority – can you identify who wrote the information, and is that person or organization a reputable resource?
Accuracy – is the information reproducible or cited by other sources?
Bias – are there conflicts of interest, i.e. is the company selling a product or do the website organizers have a specific agenda? Are the goals or aims of the website clearly stated?
Currency – when was the webpage last updated? Are the links up-to-date?
Comprehension – is the information written at an appropriate level for its audience? How does the information compare with other sources on this topic?
| Clinical Question | Suggested Best Study |
| Harm/Etiology | RCT > cohort > case control > case series |
| Clinical Exam | prospective, blind comparison to gold standard |
| Diagnosis | prospective, blind comparison to gold standard |
| Therapy | RCT > cohort > case control > case series |
| Prevention | RCT > cohort study > case control > case series |
| Prognosis | cohort study > case control > case series |
| Cost Benefit | economic analysis |
adapted from Duke Libraries' Introduction to Evidence Based Practice
(From CEBM's Glossary and Duke Libraries' Intro to Evidence-Based Practice)
Case report / Case series: A report on a series of patients with an outcome of interest. No control group is involved.
Case control study: A study which involves identifying patients who have the outcome of interest (cases) and patients without the same outcome (controls), and looking back to see if they had the exposure of interest.
Cohort study: Involves identification of two groups (cohorts) of patients, one which received the exposure of interest, and one which did not, and following these cohorts forward for the outcome of interest.
Randomized controlled clinical trial: Participants are randomly allocated into an experimental group or a control group and followed over time for the variables/outcomes of interest.
Systematic review: A summary of the medical literature that uses explicit methods to perform a comprehensive literature search and critical appraisal of individual studies and that uses appropriate statistical techniques to combine these valid studies.
Meta-analysis: A systematic review that uses quantitative methods to synthesize and summarize the results.
Cross sectional study: The observation of a defined population at a single point in time or time interval. Exposure and outcome are determined simultaneously.
Prospective, blind comparison to a gold standard: Studies that show the efficacy of a diagnostic test are also called prospective, blind comparison to a gold standard study. This is a controlled trial that looks at patients with varying degrees of an illness and administers both diagnostic tests — the test under investigation and the “gold standard” test — to all of the patients in the study group. The sensitivity and specificity of the new test are compared to that of the gold standard to determine potential usefulness.
Qualitative research: answers a wide variety of questions related to human responses to actual or potential health problems.The purpose of qualitative research is to describe, explore and explain the health-related phenomena being studied.
Retrospective cohort: follows the same direction of inquiry as a cohort study. Subjects begin with the presence or absence of an exposure or risk factor and are followed until the outcome of interest is observed. However, this study design uses information that has been collected in the past and kept in files or databases. Patients are identified for exposure or non-exposures and the data is followed forward to an effect or outcome of interest.