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Nursing program: Research skills: What is Evidence-Based Practice? (EBP)

Provides starting points for research in TCC's Nursing Program

What is evidence-based practice?

What is Evidence-Based Practice?

According the the American Association of Colleges of Nursing, evidence-based practice (EBP) is:

  • Practice based on the best available evidence that also incorporates
    • Patient values and preferences
    • Clinician judgment and expertise
  • Using evidence to guide nursing practice

See the "Finding EBP resources" page of this tab to begin searching for EBP resources.

Levels of evidence

Levels of Evidence

Levels of evidence (sometimes called hierarchy of evidence) are assigned to studies based on the methodological quality of their design, validity, and applicability to patient care. These decisions gives the grade (or strength) of recommendation.

Level of evidence Article type/s
Level 1 Systematic review & meta-analysis of randomized controlled trials; clinical guidelines based on systematic reviews or meta-analyses (filtered, secondary)
Level 2 One or more randomized controlled trials (unfiltered, primary)
Level 3 Controlled trial (no randomization; unfiltered, primary):
Level 4 Case-control or cohort study (unfiltered, primary)
Level 5 Systematic review of descriptive & qualitative studies (filtered, secondary)
Level 6 Single descriptive or qualitative study (unfiltered, primary)
Level 7 Expert opinion

Adapted from: Melnyk, B.M. & Fineout-Overholt, E. (2011). Evidence-based practice in nursing and healthcare: A guide to best practice. Philadelphia: Lippincott, Williams & Wilkins.

Filtered versus unfiltered resources

Filtered sources

As unfiltered or primary literature begins to circulate, others who were usually not involved in the original research, provide analysis, interpretation, and often synthesis of the primary literature, either of individual studies or groups of them. This is the secondary, or filtered literature. It can take the form of review articles, systematic reviews, meta-analyses, evidence summaries, or guidelines.

Unfiltered sources

The reporting and dissemination of scientific research follows a cycle. Reports of new, original research written by the scientists who conducted it are sometimes referred to as primary, or unfiltered literature. These first-hand accounts can take the form of journal articles, conference proceedings, dissertations, technical reports, or more informal online communications.

Regardless of what type of literature you're consulting, be critical! (See the Evaluating sources subpage under the "Appropriate?" tab above for more information).

How to read and critique an empirical research article

Source: "How to Read an Empirical Research Article," uploaded by MetroSverige, 2016, Standard YouTube License.

Article types

Article Types

Empirical Research Articles

Empirical research articles are reports of original scientific research, written by the scientists themselves. They can be identified by having some or all of the following characteristics:

  • Multiple authors (usually at least 3)
  • Can be quite lengthy, depending on the journal (10+ pages)
  • Long, technical titles
  • Thick in the language of the speciality, lots of jargon
  • Include an abstract
  • Divided into sections, which often include “Objectives”, “Methods”, “Discussion”, and “Results”
  • Charts, graphs, and tables
  • Lengthy references list

These are unfiltered or primary resources. These can be levels 2-4 or 6 depending on the methods used.

Literature Reviews

Literature reviews are meant to analyze and pull together – in one place -- the results of different research projects on a specific topic. They are usually written by a scholar/practitioner in the field, but not necessarily by someone who has done empirical research themselves. Literature review articles can be identified by having some or all of the following characteristics:

  • Usually just one, or maybe two, authors
  • Often brief, two or three pages
  • Titles are not necessarily technical-sounding, and may even include the word “review” in them
  • Peppered with references to other research
  • Lengthy references list

These are filtered or secondary resources. These are level 7, as the literature is typically reviewed in a nonsystematic, idiosyncratic way and conclusions can be more opinion based rather than evidence based.

Systematic Reviews

Systematic reviews are literature reviews focused on a single question that try to identify, appraise, select and synthesize all high quality research evidence relevant to that question. 

  • Systematic reviews use explicit methods to identify, select, and critically evaluate relevant research.
  • Systematic reviews minimize the possibility of bias by using explicit criteria, and expand the relevance of individual studies with limited scope, but ...
  • Only a small number of clinical topics are covered by systematic reviews, because they require years of effort to develop.

These are filtered or secondary resources. These are level 1, unless focusing on descriptive or qualitative studies (in which case they are level 5)


Meta-analyses are systematic reviews that combine the results of several studies (often clinical trials) using quantitative statistics. They may be used to evaluate therapeutic effectiveness, plan new studies, etc.

These are filtered or secondary resources. These are level 1.

Clinical Practice Guidelines

Clinical practice guidelines are systematically developed statements of appropriate care designed to assist the practitioner and patient make decisions about appropriate health care for specific clinical circumstances.

  • Guidelines from reputable, authoritative organizations are usually based on the most current, relevant research, but ...
  • Guidelines are developed using widely varying standards. Cost may be considered as well as health outcomes

These are filtered or secondary resources. These are level 1.

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