Module 9: Critical Appraisal - Center for Evidence

Report
Postgraduate Course
8. Evidence-based management
Step 3: Critical appraisal of studies
5-step approach
Postgraduate Course
EBMgt is a 5-step approach
1. Formulate an answerable question (PICOC)
2. Search for the best available evidence
3. Critically appraise the quality of the found evidence
4. Integrate the evidence with managerial expertise
and organizational concerns and apply
5. Monitor and evaluate the results
Intermezzo
Postgraduate Course
How to read a research article?
Structure of an article
Postgraduate Course
1. Title
2. Abstract
3. Introduction
4. Background / review of literature
5. Organizational context
6. Methodology
7. Results
8. Discussion
Structure of an article
Postgraduate Course
1.Title
Not always a good indication of the content of
the article
Example: “The Risks of Autonomy: Empirical Evidence for the
Necessity of a Balance Management in Promoting Organizational
Innovativeness” ??????
Structure of an article
Postgraduate Course
2. Abstract
Sometimes unclear. What should be in it:
a summary of the the research question, key
methods, results and conclusions of the study
Structure of an article
Postgraduate Course
3. Introduction
Should contain the research question (PICOC!) or
hypotheses tested
4. Background / review of literature
Research questions occur in the context of an alreadyformed body of knowledge. The background should
address this context, help set the rationale for the study,
and explain why the questions being asked are relevant.
Structure of an article
Postgraduate Course
5. Research setting (organizational context)
6. Methodology
Should describe exactly how the research was carried out:
- Sample:
characteristics, selection, number,
non-response
- Measures: description of tests / questionnaires
(validated?), data, outcome measures
- Procedure: study design (qualitative, quantitative,
controlled?)
Structure of an article
Postgraduate Course
7. Results
Should tell the reader what the findings were. All outcome
measures must be reported and confidence intervals for
effect sizes should be presented.
8. Discussion
- Interpretation of the results / relation to theory
- Comparison with the results of other studies
- Weaknesses / limitations of the study
- Implications
- Recommendations
In general
Postgraduate Course
 Don’t let yourself be taken in by scientific jargon and
complex use of language!! Good articles are written in
plain English.
 Even authorative journals with a high impact factor
contain bad articles and vice versa.
 Focus on research question, study design and outcome.
 Don’t worry about statistics!
 Be critical!! Always ask yourself: does this make sense?
Postgraduate Course
Critical appraisal of studies
Critical appraisal: quick and dirty
Postgraduate Course
Is the study design appropriate to the stated
aims?
Are the measurements likely to be valid and
reliable?
Was there a relevant effect size?
Is the outcome (population, type of organization)
generalizable to your situation?
Levels of internal validity
Postgraduate Course
1. Were there enough subjects in the study?
2. Was a control group used?
3. Were the subjects randomly assigned?
4. Was a pretest used?
5. Was the study started prior to the intervention or event?
6. Was the outcome measured in an objective and reliable way?
6x yes
= very high (A)
5x yes
= high (A)
4-3x yes
= limited (B)
2x yes
= low (C)
1-0x yes
= very low (D)
Postgraduate Course
Always ask yourself:
How did they measure that?
Is that a reliable way to measure?
Appraisal
Postgraduate Course
Critical appraisal questionnaires
www.cebma.org/ebp-tools
Standard appraisal questions
Postgraduate Course
1. Did the study address a clearly focused issue?
2. Is the sample size justified?
3. Is the design appropriate to the stated aims?
4. Are the measurements likely to be valid and reliable?
5. Are the statistical methods described?
6. Did untoward events occur during the study?
7. Were the basic data adequately described?
8. Do the numbers add up?
9. Was the statistical significance assessed?
10. What do the findings mean?
11. Are important effects overlooked?
12. What implications does the study have for your practice?
Appraisal of a controlled study
Postgraduate Course
1. Did the study address a clearly focused issue?
2. Were subjects randomly allocated to the experimental and control
group? If not, could this have introduced bias?
3. Are objective inclusion / exclusion criteria used?
4. Were groups comparable at the start of the study?
5. Are objective and validated measurement methods used and were
they similar in the different groups? (misclassification bias)
6. Were outcomes assessed blind? If not, could this have introduced
bias?
7. Is the size of effect practically relevant?
8. Are the conclusions applicable?
Appraisal of a cohort / panel study
Postgraduate Course
1. Did the study address a clearly focused issue?
2. Was the cohort / panel recruited in an acceptable way? (selection
bias)
3. Was the cohort/ panel representative of a defined population?
4. Was a control group used? Should one have been used?
5. Are objective and validated measurement methods used and were
they similar in the different groups? (misclassification bias)
6. Was the follow up of cases/subjects long enough?
7. Could there be confounding?
8. Is the size of effect practically relevant?
9. Are the conclusions applicable?
Appraisal of a case-control study
Postgraduate Course
1. Did the study address a clearly focused issue?
2. Were the cases and controls defined precisely?
3. Was the selection of cases and controls based on external, objective
and validated criteria? (selection bias)
4. Are objective and validated measurement methods used and were
they similar in cases and controls? (misclassification bias)
5. Did the study incorporate blinding where feasible? (halo-effect)
6. Was there data-dredging?
7. Could there be confounding?
8. Is the size of effect practically relevant?
9. Are the conclusions applicable?
Assessment of a survey
Postgraduate Course
1. Did the study address a clearly focused issue?
2. Was the sample size justified?
3. Could the way the sample was obtained introduce (selection)bias?
4. Is the sample representative and reliable?
5. Are the measurements (questionnaires) likely to be valid and
reliable?
6. Was the statistical significance assessed?
7. Are important effects overlooked?
8. Can the results be generalized?

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