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PAHO/WHO Collaborating Centre to Advance the Policy on Research for Health Resources

Systematic Reviews

  • Prospero (Register your Systematic Review)
  • Cochrane Handbook for Systematic Reviews
  • Standards for Systematic Reviews
  • Campbell Collaboration

Study Design & Types of Reviews

Study Design & Study Types

  • Randomized Controlled Trial - Study design that reduces potential for bias by randomly assigning participants to intervention and control groups.  An RCT allows for comparison between groups and can provide sound evidence of cause and effect. Example RCT Article
  • Cohort Study - Study design that involves following participants who are already taking a particular treatment or have a similar health condition or exposure over a period of time.  Outcomes are then compared with a similar group of people who have not been affected by the treatment, health condition, or exposure.  Cohort studies are observational in nature.  Example Cohort Study Article
  • Cross-Sectional Study - Observing and collecting data from an entire population at a defined time.  Results may be used to describe features of a population, prevalence of a health condition or cause and effect of a particular disease. Example Cross-Sectional Study Article
  • Case-Control Studies -  Example Case-Control Study Article
  • Case Study - A case study document an individual case (patient) condition.  It is generally used to identify new trends or unexplained conditions or diseases. Example Case Study Article

Additional Resources Related to Primary Research Study Design:

Review Types & Methodology

  • Critical Review -  "Aims to demonstrate writer has extensively researched literature and critically evaluated its quality.  Goes beyond mere description to include degree of analysis and conceptual innovation.  Typically results in hypothesis or model".
  • Literature Review - "Published materials that provide examination of recent or current literature.  Can cover wide range of subjects at various levels of completeness and comprehensiveness.  May include research findings."
  • Mapping Review/Systematic Map - "Map out and categorize existing literature from which to commission further reviews and/or primary research by identifying gaps in research literature."
  • Meta-analysis - "Technique that statistically combines the results of quantitative studies to provide a more precise effect of the results".
  • Mixed Studies Review/Mixed Methods Review - "Refers to any combination of methods where one significant component is a literature review (usually systematic). Within a review context it refers to a combination of review approaches for example combining quantitative with qualitative research or outcome with process studies."
  • Overview - "Generic Term: summary of the [medical] literature that attempts to survey the literature and describe its characteristics".
  • Qualitative Systematic Review/Qualitative Evidence Synthesis - "Method for integrating or comparing the findings from qualitative studies. It looks for ‘themes’ or ‘constructs’ that lie in or across individual qualitative studies."
  • Rapid Review - "Assessment of what is already known about a policy or practice issue, by using systematic review methods to search and critically appraise existing research".
  • Scoping Review - "Preliminary assessment of potential size and scope of available research literature. Aims to identify nature and extent of research evidence (usually including ongoing research)."
  • State of the Art Review - "Tend to address more current matters in contrast to other combined retrospective and current approaches.  May offer new perspectives on issue or point out area for further research."
  • Systematic Review - "Seeks to systematically search for, appraise and synthesis research evidence, often adhering to guidelines on the conduct of a review."  Example Systematic Review Article
  • Systematic Search and Review - "Combines strengths of critical review with a comprehensive search process.  Typically addresses broad questions to produce 'best evidence synthesis'."
  • Systematized Review - "Attempt to include elements of systematic review process while stopping short of systematic review. Typically conducted as postgraduate student assignment."
  • Umbrella Review - "Specifically refers to review compiling evidence from multiple reviews into one accessible and usable document.  Focuses on broad condition or problem for which there are competing interventions and highlights reviews these inSpecifically refers to review compiling evidence from multiple reviews into one accessible and usable document. Focuses on broad condition or problem for which there are competing interventions and highlights reviews that address these interventions and their results.

Descriptions reproduced from Grant, M. J., & Booth, A. (2009). A typology of reviews: An analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26(2), 91-108. doi:10.1111/j.1471-1842.2009.00848.x.  For more in-depth information about study types and designs please see the previous article and additional resources:


Databases (For ASU Affiliates)

Databases (Open Access)

  • PubMed(Medline)
  • Virtual Health Library - Regional (Americas)
  • Health Systems Evidence Database
  • Popline
  • EVIPNet

Government & Organizational Resources

  • Agency for Healthcare Research & Quality
  • PAHO Support Tools for Policy Making
  • National Academy of Medicine
  • National Institutes of Health
  • Global Health Policy Research Network

Reporting Standards

  • Equator Network

Tools & Software

Systematic Review Tools

Citation Management Tools

Data Management, Extraction, & Analysis Tools

Hours and Locations