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NURS 7220-OL: Evidence-Based Practice/Informatics

Resources and information relevant to the topics discussed in NURS 7220-OL.

Levels of Clinical Evidence in the Primary & Secondary Literature

Levels of Clinical Evidence in the Primary Literature

Type of Question

Type of Study/Methodology


Therapy:information needed about
treatments(effectiveness, cost, etc.)
Randomized Controlled Trial
Randomized Controlled Trial
double[TW] and blind [TW]
Diagnosis: information needed about a
diagnostic test (sensitivity, accuracy, etc.)
Controlled Trial Sensitivity and Specificity [MH]
Diagnosis [SH]
Prognosis: information needed about the
course of the disease over time, expected
complications, etc.
Cohort Studies
Case Control
Case Series
Cohort Studies [MH]
Prognosis [MH]
Survival Analysis [MH]
Etiology/Harm: information needed about
causes of disease or contributing factors of disease
Cohort Studies Cohort Studies [MH]
Risk [TW]
Prevention: information needed about the
prevention of disease (immunization,
social factors, etc.)

Randomized Controlled Trial

Cohort Studies

Randomized Controlled Trial [PT]
Cohort Studies [MH]
Prevention and Control [SH]

Quality Improvement: information needed
about clients' and health professionals'
experiences and concerns
Randomized Controlled Trial Randomized Controlled Trial [PT]
Practice Guideline [PT]
Consensus Development Conference [PT]

(Abbreviations: MH=Medical Subject Heading; PT=Publication Type; SH=Subheading; TW=Text Word)

Secondary Literature

This secondary literature synthesizes, filters, and evaluates the primary research literature. 

Filtered or Synthesized Information Description/Definition How to Find This Type of Information
Systematic Reviews
  • differ from traditional review articles in that conclusions are evidence-based rather than commentary
  • start with a clearly articulated question
  • use explicit, rigorous methods to identify, critically appraise, and synthesize relevant studies
  • appraise relevant published and unpublished evidence before combining and analyzing data
  • include description of how primary data sources are identified
  • assess individual studies for validity

Use Cochrane 

  • Cochrane Database of Systematic Reviews
  • Cochrane Controlled Trials Register
  • Cochrane Review Methodology Database

Use PubMed/MEDLINE searching

  • Review [PT] AND medline [TW](Quantitative OR Systematic OR Methodologic) AND (Review OR Overview)

Use PubMed Clinical Queries

  • "Systematic Review" is available as a limit option

Use CINAHL Plus with Full Text  select Systematic Review in the Publication Type box

  • specific methodologic and statistical technique for combining quantitative data
  • type of systematic overview

Use Cochrane 

Use PubMed/MEDLINE searching

  • Meta-analysis [PT]
  • meta-anal* [TW] OR
  • metaanal* [TW]
Evidence-Based Practice Guidelines
  • gather, appraise, combine evidence systematically
  • include statements designed to assist practitioner and patient decisions
  • developed by professional groups, government agencies, local practices
  • include a structured abstract: objective, option, outcomes, evidence, values, benefits/harms/costs, recommendation, validation, sponsors

Use National Guideline Clearinghouse

Use Agency for Healthcare Research and Quality

Use US Preventive Services Task Force Recommendations

Through different associations and organizations

Critically Appraised Topics (CATs)
  • scan literature for clinically relevant studies
  • critically appraise the studies
  • provide commentary on strength of study and clinical significance
  • provided in a one-page format

Use EBM Reviews

  • ACP Journal Club
  • Essential Evidence Plus
  • Evidence-Based Nursing

Use CATmaker software from CEBM

Decision Analyses/Decision Tools
  • studies that analyze decisions faced by clinicians for an individual patient, about clinical policy, or a global health care policy
  • application of explicit, quantitative methods to analyze decisions under conditions of uncertainty
  • risks and benefits of a decision are made fully explicit
  • decision tree is included

Use PubMed/MEDLINE searching

  • Decision Support Techniques [MH]
  • Cost-Benefit Analysis [MH]
  • decision analysis [TI]
Consensus Development Reports
  • assessments of emerging or critical health issues based on available research and expert opinion to identify needs for policy development and further research (description based on information from the NIH Consensus Development Program now 'retired' in light of "many other organizations that conduct [evidence] reviews")

Use PubMed/MEDLINE searching

  • "consensus statement" [TW] OR "consensus report" [TW]

(Abbreviations: MH=Medical Subject Heading; PT=Publication Type; SH=Subheading; TW=Text Word)

*Tables adapted from

Primary Research Articles

Will include a section called "method" or "methodology." This can appear in either/or the abstract or the article.

Will include a section called "results."

Words to look for as clues include:

Analysis, Study, Investigation, Examination, Surveys or Experiment.

Primary Sources & Secondary Sources Explained

During the course of your research, you might be asked to use primary and secondary sources. 'What is the difference?', you ask.

Primary sources

  • Are those which were written during the period in which the information occurred
  • Primary sources are not necessarily the sources you primarily use, but they are the most fundamental information on the topic
  • Published at the time the event occurred, by someone in the actual event
  • For historical events, a primary source on Abraham Lincoln would be either one written by Lincoln (such as the Gettysburg Address) or by someone who knew Lincoln. They could be documents or artifacts created during the time period

Secondary sources

  • Are those reviews and accounts written AFTER an event occurred
  • Secondary sources analyze and interpret primary sources and are used primarily for presenting the views of others about your primary sources
  • For historical events, a secondary source on Abraham Lincoln could be a book, magazine article, or internet site written after his death
  • For topics in the Nursing/Medical field, a secondary source might be an article written about a procedure and then evidence described about its effects.  The Primary source would be an article written about the procedure written by the person who developed the procedure 

  What Types of Articles/Studies are Primary?

  • pilot/prospective studies
  • cohort studies
  • term projects
  • survey research
  • case studies
  • qualitative studies (participant observation, interviews, surveys)
  • experimental research (randomized clinical trials/RCTs)
  • double blind method
  • systematic reviews of the above