LibGuides: Evidence-Based Research: Primary & Secondary Literature

Primary Literature

Examples with Medline

Type of Question	Type of Study/Methodology	MEDLINE Filters
Therapy: information needed about treatments (effectiveness, cost, etc.)	Double-Blind Randomized Controlled Trial	Randomized Controlled Trial [PT] 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. Dissemination and incorporation of valid clinical research findings into medical practice is the ultimate goal. Examples with Cochrane, PubMed, Medline

Systematic Reviews
Meta-Analyses
Critically Appraised Topics
Decision Analyses/Decision Tools
Evaluated Bibliographic Databases
Practice Guidelines
Consensus Development Reports

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-appraise relevant published and unpublished evidence before combining and analyzing data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

*Cochrane Database of Systematic Reviews

*In MEDLINE:
Review [PT] AND medline [TW]
(Quantitative OR Systematic OR Methodologic) AND (Review OR Overview)

*In PubMed:

Clinical Queries "Systematic Review" is available as a limit option.

META-ANALYSES

-specific methodologic and statistical technique for combining quantitative data

-type of systematic overview

*Cochrane Database of Systematic Reviews

*In MEDLINE:
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

*National Guideline Clearinghouse

*Agency for Healthcare Research and Quality

*US Preventive Services Task Force Recommendations

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

*Critically Appraised Worksheet and Guidelines

*CATmaker software from CEBM

DECISION
ANALYSES

-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

*In MEDLINE:

Decision Support Techniques [MH]

Cost-Benefit Analysis [MH]

decision analysis [TI]

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

MEDLINE with Full Text This link opens in a new window Provides full text for nearly 1,200 journals indexed in MEDLINE, including more than 1,400,000 full-text articles dating back to 1965.
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Cochrane Library This link opens in a new window A collection of evidence-based health care resources including Cochrane Reviews, the Cochrane Controlled Trials Register, NHS Economic Evaluation Database, Health Technology Assessment Database, and the Cochrane Methodology Register. The Cochrane Reviews are provided in full text.
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