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Occupational Therapy at UTM

OT/OS Program at UTM 2018-2019

What Are Systematic Reviews?

“A systematic review attempts to identify, appraise and synthesize all the empirical evidence that meets pre-specified eligibility criteria to answer a given research question. Researchers conducting systematic reviews use explicit methods aimed at minimizing bias, in order to produce more reliable findings that can be used to inform decision making.”

- Cochrane Library, About Cochrane Systematic Reviews and Protocols

“Library books,” CCAC North Library

Systematic Reviews are comprehensive analyses of all the scientific research on a specific question. They answer the question: what does the evidence say about this medical issue?

Systematic reviews are crucial to medical practice and research. They are a valuable resource for clinicians deciding on treatments, and they also reveal gaps in current research.

A systematic review is not the same as a narrative review or a literature review. Unlike other kinds of reviews, systematic ones must be as thorough and unbiased as possible, and must also make explicit how the search was conducted.

“Research - IMG_1367,” Nicola 

A true systematic review:

  • Is produced by at least two people
  • Usually takes between 9 and 12 months
  • Involves rigorous checks for thoroughness and bias

If you are a student, you're probably not conducting a systematic review in the true sense, but are working on a systematic review-like project.

What are scoping reviews?

A scoping study can be defined as:"..a form of knowledge synthesis that addresses an exploratory research question aimed at mapping key concepts, types of evidence, and gaps in research related to a defined area or field by systematically searching, selecting and synthesizing existing knowledge."  (from:  Colquhoun, H. L., Levac, D., O'Brien, K. K., Straus, S., Tricco, A. C., Perrier, L., . . . Moher, D. (2014). Scoping reviews: Time for clarity in definition, methods, and reporting.  Journal of Clinical Epidemiology,(12), 1291-1294. ).

Common reasons for conducting a scoping study:

  1. Examine the extent, range and nature of research activity
  2. Determine the value of undertaking a full systematic review (e.g. do any studies exist?  Have systematic reviews already been conducted?)
  3. Summarize and disseminate research findings
  4. Identify gaps in existing body of literature

(from Arksey, H., O'Malley, L. (2005). Scoping studies: towards a methodological framework. International Journal of Social Research Methodology, 8(1): 19-32.)

Scoping studies typically involve six steps:

  1. Identify the research question
  2. Identify relevant studies
  3. Select studies to include
  4. Extract & charting  data from included studies
  5. Collate, summarize & report results
  6. Consultation with stakeholders

Differences between systematic and scoping reviews

Scoping studies differ from systematic reviews in several ways:

  Scoping review Systematic review
Research question Broadly defined Highly focused
Inclusion/Exclusion criteria Developed post hoc at study selection stage Developed at protocol stage
Study selection All study types Defined study types
Data extraction “Charts”  data according to key issues, themes, etc. Synthesizes & aggregates findings

HOWEVER both systematic reviews and scoping reviews require comprehensive and structured searches of the literature to maximize recall and decrease bias.


Additional information:

Guide to Knowledge Synthesis from Canadian Institutes of Health Research (CIHR)

Arksey, H., & O'Malley, L. (2005). Scoping studies: Towards a methodological framework.  International Journal of Social Research Methodology: Theory and Practice, 8 (1), 19-32. doi:10.1080/1364557032000119616


Difference between narrative reviews and evidence syntheses

Evidence syntheses differ from traditional narrative or literature reviews in several ways:

Narrative review Evidence Synthesis
Search methods not systematic, nor validated, nor peer reviewed systematic, highly structured to minimize bias ; conducted much like other scientific studies
Inclusion/Exclusion criteria Not explicitly stated Included in protocol or developed post hoc
Bias potential for authors to selectively include or exclude studies to support a position attempts to minimize bias based on protocol, non-selective reporting of outcomes and transparent and reproducible search strategies
Replication & updating Difficult since search methodology not reported in detail in methods section nor included in full in the appendices Designed to be reproducible and facilitate updating