Evidence-based models use a process for framing a question, locating, assessing, evaluating, and repeating as needed. PICO elements include: Problem/Patient/Population, Intervention/Indicator, Comparison, Outcome, and (optional) Time element or Type of Study.
1. Frame the Question
P (problem, patient, or population): hospital acquired infection
I (intervention/indicator): hand washing
C (comparison): no hand washing; other solution; masks
O (outcome of interest): reduced infection
2. Plan a Search Strategy
P (Problem/Patient/Population) in Natural Language: hospital acquired infection
P (Problem/Patient/Population) in Database Vocabulary: cross infection [MeSH] / cross infection [CINAHL Subject]
I (Intervention/Indicator) in Natural Language: hand washing
I (Intervention/Indicator) in Database Vocabulary: hand disinfection [MeSH] / handwashing [CINAHL Subject]
3. Consider Comparison, Outcome, Time Factors or Type of Study
After viewing the initial search results you may decide to narrow your search with terms for the comparison, outcome, time factors or type of study. You may view results, abstracts, and full text of articles to view the comparison and outcome elements. Use database filters explained in "Filtering the Evidence."
4. Filter the Evidence
Reference (box taken from):
NYU Libraries. (2020, November 6). Health (nursing, medicine, allied health): Search strategies: Framing the question (PICO). Retrieved from https://guides.nyu.edu/c.php?g=276561&p=1847897.
Background and Foreground Questions: Clinical questions can be categorised as either background or foreground. Determining the type of question will help you to select the best resource to consult for your answer.
Background questions ask for general knowledge about a condition, test or treatment. These types of questions typically ask:
who, what, where, when, how, & why about things like a disorder, test, or treatment, or other aspect of healthcare. For example:
Foreground questions ask for specific knowledge to inform clinical decisions. These questions typically concern a specific patient or particular population. They tend to be more specific and complex than background questions. Quite often, foreground questions investigate comparisons, such as two drugs, or two treatments. For example:
Reference (box taken from):
University of Canberra Library. (2020, September, 9). Evidence-based practice in health. https://canberra.libguides.com/c.php?g=599346&p=4149723
Primary Question Types
Additional Question Types
Duke University Medical Center & Archives. (2020, June 25). Evidence-based practice: PICO. Retrieved from https://guides.mclibrary.duke.edu/ebm/pico.
Duke University Medical Center Library. (2005). Evidence-based medicine resources. https://mclibrary.duke.edu/sites/mclibrary.duke.edu/files/public/guides/ebmresources.pdf#:~:text=A%20study%20that%20shows%20the%20efficacy%20of%20a,to%20all%20of%20the%20patients%20in%20the%20study.
This is a "technique that statistically combines the results of quantitative studies to provide a more precise effect of the results" (Grant & Booth, 2009).
Systematic Review: Meta-Analysis:
A systematic review "seeks to systematically search for, appraise and synthesis research evidence, often adhering to guidelines on the conduct of a review" (Grant & Booth, 2009).
Randomized Controlled Trial:
"A trial in which participants are randomly assigned to two or more groups: at least one (the experimental group) receiving an intervention that is being tested and another (the comparison or control group) receiving an alternative treatment or placebo. This design allows assessment of the relative effects of interventions" (Dahlgren Memorial Library, 2020).
Controlled Clinical Trial:
"A trial in which participants are assigned to two or more different treatment groups. In Clinical Evidence, we use the term to refer to controlled trials in which treatment is assigned by a method other than random allocation. When the method of allocation is by random selection, the study is referred to as a randomized controlled trial (RCT). Non-randomized controlled trials are more likely to suffer from bias than RCTs" (Dahlgren Memorial Library, 2020).
"Cohort studies follow one group that is exposed to an intervention of interest and another group that is non‐exposed to determine the occurrence of the outcome (the relative risk). Cohort studies can examine multiple outcomes of a single exposure" (Lu, 2009).
Case Control Study:
A case control study "examines a group of people who have experienced an event (usually an adverse event) and a group of people who have not experienced the same event, and looks at how exposure to suspect (usually noxious) agents differed between the two groups. This type of study design is most useful for trying to ascertain the cause of rare events, such as rare cancers" (Dahlgren Memorial Library, 2020).
"Analysis of series of people with the disease (there is no comparison group in case series)" (Dahlgren Memorial Library, 2020).
"Case reports provide anecdotal evidence by describing single cases. Description often includes the manifestations, clinical course, prognosis, how clinicians diagnosed and treated the condition and the clinical outcome" (Lu, 2009).
Prospective, Blind Comparison to a Gold Standard Study:
Prospective, blind comparison to a gold standard studies show "the efficacy of a diagnostic test is called a 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" (Duke University Medical Center Library, 2005).
Dahlgren Memorial Library. (2020, October 27). Evidence-based medicine resource guide. Retrieved fromhttps://guides.dml.georgetown.edu/ebm/ebmclinicalquestions. (Dahlgren Memorial Library, 2020).
Duke University Medical Center Library. (2005). Evidence-based medicine resources. https://mclibrary.duke.edu/sites/mclibrary.duke.edu/files/public/guides/ebmresources.pdf#:~:text=A%20study%20that%20shows%20the%20efficacy%20of%20a,to%20all%20of%20the%20patients%20in%20the%20study
Grant, M. J., & Booth, A. (2009). A typology of reviews: An analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26, 91–108. https://doi.org/10.1111/j.1471-1842.2009.00848.x.
Lu, C. Y. (2009, April 3). Observational studies: A review of study designs, challenges and strategies to reduce confounding. International Journal of Clinical Practice, 63(5), 691-697. doi:10.1111/j.1742-1241.2009.02056.x
(Least Biased) Systematic Reviews < Critically-Appraised Topics < Critically-Appraised Individual Articles. (Most Biased) (Mentzer, 2020).
(Least Biased) Randomized Control Trial < Cohort Study < Case Control Study < Cross Sectional Study. (Most Biased) (Claude Moore Health Sciences Library, 2020).
Claude Moore Health Sciences Library. (2020, September 1). Evidence based practice. Retrieved from https://guides.hsl.virginia.edu/c.php?g=921177&p=6638624.
Mentzer, K., (2020, October 13). Evidence-based practice for health professionals: Levels of evidence. Retrieved from https://libguides.nvcc.edu/c.php?g=361218&p=2439383.