Systematic Reviews & Other Review Types

A  comprehensive syntheses of two or more types of data (e.g. quantitative and qualitative) are conducted and then aggregated into a final, combined synthesis

OR

Qualitative and quantitative data are combined and synthesized in a single primary synthesis.

(The Joanna Briggs Institute 2014 Reviewers Manual)

Mixed Methods Reviews are best designed for:

• Multidisciplinary topics or topics with a body of literature that includes quantitative, qualitative, and mixed methods studies.
• To determine not only the effects of interventions but also their appropriateness.
• To identify research gaps.
• To provide an explanation for possible heterogeneity between trials.
• To answer multiple questions in one systematic review.
• "Integrate quantitative estimates of benefit and harm with more qualitative understanding from people's lives."

(Harden A. 2010)

Timeframe: 12-18+ months.  Same as a systematic review or longer. 

Question: Addresses 2 or more specific PICO criteria, "Mixed methods reviews should pose a question that specifically requires the inclusion of two or more syntheses that are grounded in different approaches".  A priori review protocol is recommended.

Examples of and clearly articulated PICO questions that may be posed by one mixed methods systematic review are:

1. What is the effectiveness of educational strategies associated with insulin pump therapy?

2. What is the appropriateness of educational strategies associated with insulin pump therapy”

Sources and searches: Types of studies and their findings are mixed.  This requires a very broad search or multiple structured searches. "This should address each of the syntheses included in the review...[and] aims to find both published and unpublished studies."

Selection: Based upon inclusion criteria.  

• "The quantitative component of the review will consider any experimental study design including randomized controlled trials, non-randomised controlled trials, quasi-experimental, before and after studies for inclusion."
• The qualitative component  The textual component of the review will consider expert opinion, discussion papers, position papers and other text.

Appraisal: "This should address each of the syntheses included in the review."  The appropriate critical appraisal tool or method should be applied by study type or there should be one general tool used that will represent all study designs.  

Synthesis: Depends on findings and included studies, applying mixed synthesis methods (qualitative:thematic synthesis/meta-ethnography & quantitative:statistical meta-analysis).  “The results of each single method synthesis included in the mixed method review will be extracted in numerical, tabular or textual format."

(Source: Joanna Briggs Institute 2014)

• May result in a larger number of citations.
• Requires more search time to create multiple searches for varying outcomes.
• There are no universally adopted methods for conducting Mixed Methods Reviews.
• Requires significant methodological skill.
• Resource intensive--may take time to engage with the evidence and develop theory.
• Not inherently reproducible or transparent because of the highly iterative nature of the interpretative process.

(Source: M. Petticrew et al (2013)

Mixed Research Synthesis, Mixed Methods Synthesis, Mixed Methods Systematic Review, Mixed Studies Review, Qualitative & Quantitative Systematic Review

Adapted with permission from Temple University Libraries. https://guides.temple.edu/systematicreviews