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| Resource Guides | Nursing Pathfinders | Evidence-Based Practice in Nursing

Evidence-Based Practice in Nursing

Visit our PICO Research Question Resource Guide to learn more about formulating a PICO question.

Created 4/2021

 What is Evidence-based Practice?

What is Evidence-based Practice?

 Evidence-based practice is the explicit use of current, best evidence in making clinical decisions regarding individual patient care. Evidence-based practice integrates:

  • The best evidence from well-designed studies.
  • A patient’s preferences or values.
  • A clinician’s expertise from evidence gathered from the patient’s data.

Evidence-based Practice Venn Diagram

Using evidence-based practice will help you make informed and personalized treatment decisions and deliver high quality health care to your patients.

Watch this video introducing evidence-based practice from the Iowa State University Library.

There are 5 steps used in the evidence-based processes. These 5 steps include:

  • Ask: formulate an answerable clinical question.
  • Acquire: search the literature to find the best evidence.
  • Appraise: look at evidence for its value and usefulness.
  • Apply: integrate the results into your clinical practice.
  • Assess: evaluate the effectiveness of the outcomes.

Evidence-based Practice Process

 How do I Formulate a Clinical, or PICO, Question?

How do I Formulate a Clinical, or PICO, Question?

Knowing how to form a PICO question is important for finding evidence that supports your clinical practices. A PICO question focuses the scope of your results and helps you develop keywords to search for evidence. Watch this video to learn more about why PICO questions are important. Also, visit our PICO Research Question Resource Guide to learn more about formulating a PICO question.

PICO Components

Ask background questions and foreground questions to learn more about your clinical question.

  • Background questions provide the basics for a greater grasp of the concepts. These are typically found in textbooks, encyclopedia, or reviews.
    • Not normally asked when clinical decisions are needed to be made about a patient
  • Foreground questions provide specific knowledge to inform clinical decisions. These are typically found in journals and conference proceedings.
    • Require a grasp of the basic concepts from background questions

Think about inclusion and exclusion criteria to help you select and set boundaries for your searching.

  • Inclusion: Elements that must be present to be eligible for inclusion. For example: 
    • Certain types of studies, certain geographic locations, published within last 5 years, comparison of certain treatments
  • Exclusion: Elements that disqualify the study from inclusion. For example:
    • Use of wrong types of studies, published more than 5 years ago, published in another language (depending on if you can read the language or are looking for articles only pertaining to the U.S.)
 Where do I Search for Literature?

Where do I Search for Literature?

The following nursing databases are recommended to search for evidence-based articles:

  • CINAHL Complete
    • Check the “Evidence-Based Practice” filter in the Limit Your Results box

Evidence-based practice limitation

Publication Types on CINAHL Complete

    • Narrow down results to “Meta-analyses”“Systematic Reviews”or “Randomized Controlled Trials” in the Publication Type filter in the Limit Your Results box. 
  • Cochrane
    • After searching your results, choose the Cochrane Reviews tab in the resultCochrane Reviews Tabs section to find Meta-analyses and Systematic Reviews.


    • After searching your results, choose the Trials tab in the results section to find Randomized Controlled Trials, Cohort Studies, and Control Studies.
    • Take a look at our Cochrane PICO Search Beta tips on our PICO Research Questions Resource Guide
  • PubMed
    • Add “AND meta-analysis”, “AND randomized controlled trial”, or “AND systematic[sb]” to your search to find these types of articles. 

Search Box in PuBMed

    • Click on the Clinical Queries link (under the Find heading) at the bottom of the homepage to limit your results to clinical studies or systematic reviews. (PubMed Clinical Queries)

PubMed Clinical Queries

 Levels of Evidence

What Types of Evidence is Needed?

Evidence Pyramids rank research types based on the rigor of evidence provided in the study. High level evidence from the top of the pyramid is preferred but may not be available for all questions. The type of questions that you are asking determines which types of studies are most appropriate.

Pyramid of Evidence

Watch this video to find out more about the types of literature in the Evidence Pyramid.

Filtered Information (Secondary Literature)  
Meta-analysis Systematic reviews that use quantitative methods to summarize results.
Systematic Review   Rigorous method of identifying, critically appraising, and synthesizing literature for a specific topic.
Critically Appraised Topic and Articles   Evaluation/synthesis of multiple research studies or of an individual research article.
Unfiltered Information (Primary Literature)    
Randomized Controlled Trials (RCTs) Randomized group of patients in experimental and control groups. Followed up for variables/outcomes of interest.
Cohort Study Two groups of patients that received exposure or did not, followed forward for outcome of interest.
Case-Control Study Comparison of patients with outcome of interest and control patients without outcome to see if they had exposure of interest.
Background Information Handbooks, encyclopedias, textbooks that provide good foundation or introduction to topic.

Different types of clinical questions can be best answered by different types of research studies. If you cannot find a study with the highest level of evidence, work your way down the Evidence Pyramid until you find a study on your topic. Here are study designs best suited to each type of clinical question:

Clinical Question Suggested Research Design
All Clinical Questions Systematic review, meta-analysis
Therapy Randomized controlled trial, meta-analysis
Etiology Randomized controlled trial, meta-analysis, cohort study
Diagnosis Randomized controlled trial
Prevention Randomized controlled trial, meta-analysis
Prognosis Cohort study
Meaning Qualitative study
Quality Improvement   Randomized controlled trial
Cost Economic evaluation

 How do I Appraise My Literature?

How do I Appraise My Literature?

Keep the following criteria in mind when you are appraising your literature:

  • Validity: Look for trials that mimic clinical practice with outcomes that make sense. The outcomes should be large, useful, and statistically significant.
    • Did the experiment demonstrate a cause-effect relationship between the independent and dependent variables?
  • Reliability: Examine the numerical data reported for trials to see if they have large numbers of patients to avoid the random chance that leads to wrong outcomes.
    • Are the results of the experiment replicable in clinical practice? Is the research methodology described in detail so the experiment can be repeated
  • Applicability: Evaluate the study’s patients in comparison with the patients that the evidence will be applied to.

Watch this video to learn more questions to ask during evidence appraisal. Or use these evidence tools to appraise your research article:

 Other Online Resources

The following online resources are recommended for learning more about evidence-based practice:

PICO Resources