VCU Libraries

Research Guides

Systematic Reviews

Guide that helps users to understand what a systematic review entails, as well as provide resources to do one.

Typology of Reviews

Adapted from: Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Info Libr J. 2009 Jun;26(2):91-108. doi: 10.1111/j.1471-1842.2009.00848.x. Review. PubMed PMID: 19490148.

Label Description Search Appraisal Synthesis Analysis


Literature Review

Generic term: 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.

May or may not include comprehensive searching.

May or may not include quality assessment.

Typically narrative.

Analysis may be chronological, conceptual, thematic, etc.


Systematic Review


Seeks to systematically search for, appraise and synthesize research evidence, often adhering to guidelines on the conduct of a review.

Aims for exhaustive, comprehensive searching.

Quality assessment may determine inclusion/exclusion.

Typically narrative with tabular accompaniment.

What is known; recommendations for practice. What remains unknown; uncertainty around findings, recommendations for future research.


Technique that statistically combines the results of quantitative studies to provide a more precise effect of the results.

Aims for exhaustive searching. May use funnel plot to assess completeness. Quality assessment may determine inclusion/exclusion and/or sensitivity analyses.

Graphical and tabular with narrative commentary.

Numerical analysis of measures of effect assuming absence of heterogeneity.


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).

Completeness of searching determined by time/scope constraints. May include research in progress.

No formal quality assessment.

Typically tabular with some narrative commentary.

Characterizes quantity and quality of literature, perhaps by study design and other key features. Attempts to specify a viable review.


Resources - Creating a Plan

PICO is a mnemonic that will help you identify the key concepts of a research question that will be used to search within research databases. 

Example Research Question: In women with uncomplicated fatigue, do iron supplements compared to no supplements reduce fatigue without major side effects?*

Patient, Population or Problem

How would I describe a group of patients similar to mine?

Example: Women with uncomplicated fatigue


Which main intervention, exposure, or prognostic factor am I considering?

(drug/treatment, diagnostic/screening test, etc)

Example: Iron supplements

Comparison (if appropriate)

What is the main alternative to compare with the intervention?

(placebo, standard therapy, gold standard, no treatment)

Example: No supplements


What can I hope to accomplish, measure, improve, affect?

(reduced mortality/morbidity, improve quality of life, accurate/timely diagnosis)

Example: Reduce fatigue; no major adverse effects

Type of Question 

How would I categorize this question (therapy, diagnosis, prognosis, etiology/harm)?

Example: Therapy

Type of Study 

What would be the best study design in order to answer this question? 

Example: Randomized Controlled Trials

*Example is based on Connie Schardt and Megan von Isenburg's EBP and the Medical Librarian course materials.

Systematic Review Timeline

  Typical timeline for a systematic review 

          Month                   Activity

           1 – 2                   Preparation of protocol.

           3 – 8                   Searches for published and unpublished studies.

           2 – 3                   Pilot test of eligibility criteria.

           3 – 8                   Inclusion assessments.

           3                        Pilot test of ‘Risk of bias’ assessment.

           3 – 10                 Validity assessments.

           3                        Pilot test of data collection.

           3 – 10                 Data collection.

           3 – 10                 Data entry.

           5 – 11                 Follow up of missing information.

           8 – 10                 Analysis.

           1 – 11                 Preparation of review report.

           12 –                    Keeping the review up-to-date.


 Source: Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from Courtesy of the University of Maryland HS/HSL.

Systematic Review Software

Grey Literature

Grey literature are publications that are informally published and unpublished materials.  Some of the items included in this category are white papers, conference abstracts, technical reports, statistical reports, theses, dissertations and clinical trial registries.