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Nursing Resources: A Self-Paced Tutorial and Refresher: 2.1 Locating the Best Evidence

An online instructional tool to orient users to the NYU virtual environment: books, databases, articles, more.

Evidence Based Nursing

Evidence-Based Nursing (EBN) is defined as:

"the application of valid, relevant, research-based information in nurse decision-making...used alongside our knowledge of our patients (their symptoms, diagnoses, and expressed preferences) and the context in which the decision is taking place (including the care setting and available resources), and in processing this information we use our expertise and judgement" (Cullum, 2008).

Only a small percentage of the published literature contains evidence that is ready for clinical application. It is estimated that only 1 in 5000 ideas eventually makes it through all of the trials and the research stages to produce evidence with clinical outcomes (McKibbon, Wilczynski, Eady, & Marks, 2009).

A literature search for the highest level of evidence -- one that applies more rigorous criteria -- filters for articles that use higher quality methodologies.

Evidence is hierarchical and spans a range of publication types:

  • Systematic reviews: (Authors of a systematic review ask a specific clinical question, perform a comprehensive literature search, eliminate the poorly done studies and attempt to make practice recommendations based on the well-done studies. A meta-analysis is a systematic review that combines all the results of all the studies into a single statistical analysis of results.)
  • Critically appraised topics (evidence syntheses)
  • Critically appraised articles (authors evaluate and synopsize individual research studies)
  • Randomized controlled trials: "Experiments in which individuals are randomly allocated to an experimental or control group in order to test the value or efficiency of a treatment or intervention" (CINAHLPlus Scope Note)
  • Cohort studies
  • Ideas, opinions, editorials, an article in a newsletter or non-peer-reviewed publication
  • Case reports
  • Background information, or any of a number of other publication types

Models of EBP describe the evidence-based process in 5 steps:

  1. Develop an answerable question.
  2. Locate the best evidence.
  3. Critically appraise the evidence.
  4. Integrate the evidence into practice using clinical expertise with attention to patient's values and perspectives.
  5. Evaluate outcome(s).

    (Flemming, 1998; McKibbon, Wilczynski, Eady, & Marks, 2009; Melnyk & Fineout-Overholt, 2010)


Retrieval of published research-based evidence begins with Step 1: Develop an answerable question.

Click on the Forward button to go to Module 2.2






Cullum, N. (2008). Evidence-based nursing: An introduction. Oxford: Malden, MA: Blackwell Pub./BMJ Journals/RCN Pub.

Flemming, K. (1998). Asking answerable questions. Evidence-Based Nursing, 1 (2), 36–37.

McKibbon, A., Wilczynski, N., Eady, A., & Marks, S. (2009). PDQ evidence-based principles and practice. (2nd ed.). Shelton, CT: People’s Medical Publishing House.

Melnyk, B. M., & Fineout-Overholt, E. (2010). Evidence-based practice in nursing and healthcare: A guide to best practice. Philadelphia, PA: Lippincott Williams & Wilkins.

Research Design

Understanding Research Study Designs (from the University of Minnesota)

Case Series and Case Reports
Case Control Studies
Cohort Studies
Randomized Controlled Studies
Double Blind Method
Meta Analyses
Systematic Reviews