Week 4: Systematic Review and Meta-Analysis
Why should you avoid grey literature?
- To avoid publication bias
What is a cohort study?
- big sample size of people who share a common characteristic.
Why do we conduct systematic reviews?
- They are key elements of evidence-based practice - To thoroughly learn the state of science on a phenomenon - To avoid reaching erroneous conclusions that could arise from a biased review.
Step 3: Search Strategy
- Identify electronic databases to use. - Identify additional search strategies (ancestry approach) - Decide whether or not to pursue the "grey literature" (unpublished reports) - Identify keywords for the search <-- think creative and broad
Question: After identifying the research question to be tested for a meta-analysis, what task would the researcher complete next?
- Identify sampling criteria. *before developing a search strategy, figure out the criteria you will follow (including/excluding criteria)
What is MOOSE?
- Meta-Analysis of Observational Studies in Epidemiology - Guides reporting of Meta-Analyses of observational studies.
What's the criteria for using Meta-Analysis in Systematic Review?
- Must decide whether statistical integration is suitable. - Research question or hypothesis should be essentially identical across studies. <-- Avoid the "fruit problem-don't combine apples and oranges! - Must have sufficient knowledge base; must be enough studies of acceptable quality - Results can be varied but not totally at odds.
What are the forms of Systematic Reviews?
- Narrative, qualitative integration (traditional review of quantitative or qualitative results) - Meta-analysis - Meta-synthesis
Which 2 groups of people developed Meta-Synthesis Approaches?
- Noblit and Hare - Sandelowski and Barroso's
What are the advantages of a Meta-Analysis?
- Objectivity—statistical integration eliminates bias in drawing conclusions when results in different studies are at odds. - Increased power—reduces the risk of a type II error compared to a single study - Despite these advantages, meta-analysis is not always appropriate. Indiscriminate use has led critics to warn against potential abuses.
What are the approaches that Meta-analysts take when handling study quality?
- Omit low-quality studies (intervention studies, non-RCTs) -Give more weight to high-quality studies - Analyze low and high quality studies to see if effects differ (sensitivity analyses)
Step 2: Sampling Criteria
- Outcome Variables - Target Population - Language - Publication date - Quality
What are the 2 Reporting Guidelines?
- PRISMA - MOOSE
What is PRISMA?
- Preferred Reporting Items for Systematic reviews and Meta-Analyses. - It's useful for writing up a systematic review of RCTs.
What is Meta-Analysis?
- Statistical integration of QUANTITATIVE results used to compute common effect size.
True/False: Evidence-based practice relies on rigorous integration of research evidence on a topic through systematic reviews.
- TRUE - Evidence-based practice relies on rigorous integration of research evidence on a topic through systematic reviews. A systematic review methodically integrates research evidence about a specific research question using carefully developed sampling and data collection procedures that are spelled out in advanced in a protocol.
What is Meta-Synthesis?
- Terminology relating to QUALITATIVE integration is diverse and complex. - Metasynthesis is an umbrella term, broadly representing "a family of methodological approaches to developing new knowledge based on rigorous analysis of existing qualitative research findings." - Metasynthesis is not a literature review. - Integrations that are more than the sum of the parts—novel interpretations of integrated findings.
What was Sandelowski and Barroso's approach to Meta-Analysis?
- Their approach distinguishes studies that are SUMMARIES (no conceptual reframing) and SYNTHESES (studies involving interpretation and metaphorical reframing). - Both summaries and syntheses can be used in a meta-summary, which can lay a foundation for a meta-synthesis.
What is Meta-Synthesis?
- Theoretical integration and interpretation of QUALITATIVE findings.
What are the objectives for this week?
-Understand the definitions of systematic review, meta-analysis, and meta-synthesis. - Describe the steps of conducting a systematic review or meta-analysis, pay attention to the literature search procedure, literature screening according to inclusion and exclusion criteria or eligibility criteria, and study quality evaluation.
What are the 7 steps in a Systematic Review?
1. Formulating the problem: delineate research question or hypothesis to be tested. 2. Designing the study: Identify SAMPLING CRITERIA for studies to be included. 3. Searching Literature: develop and implement a search strategy. 4. Evaluating Study Quality: Locate and screen sample of studies meeting the criteria. 5. Extracting and encoding data for analysis 6. Analyzing the data 7. Reporting the findings.
Step 4: Study Quality Evaluation
Evaluations of study quality can use: - A scale approach (use a formal instrument to "score" overall quality) - A component approach (code whether certain methodologic features were present or not) <-- randomization, blinding, low attrition
What are steps 5,6, and 7 in the Systematic Review?
Step 5: Extracting and encoding data for analysis Step 6: Analyzing the data Step 7: Reporting the findings
What was Noblit and Hare's approach to Meta-Synthesis?
They developed and approach for a Meta-Ethnography> - Suggest a 7 stage approach - Involves "translating findings from qualitative studies into one another. - "An adequate translation maintains the central metaphors and/or concepts of each account." - Final step is synthesizing the translation.
