1. Critical Appraisal of
Published Medical Research
Dr. Tarek Tawfik
11/27/13
Dr Tarek Amin
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2. Consider the study design
Consider the outcome variable
Consider the predictor variables
Consider the methods of analysis
Consider the possible source of bias
Consider the interpretation of results
11/27/13
Consider the utility of the results
Dr Tarek Amin
Steps in evaluation of a published paper
Consider the research hypothesis
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3. Stepwise Approach for Appraisal.
Step 1. Consider the research hypothesis
Is there a clear statement of the
research hypothesis?
Does the study address a question that
has clinical relevance?
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Dr Tarek Amin
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4. Step 2. Consider the Study Design
Is the study design appropriate for the
hypothesis?
Does the design represent an advance over
prior approaches?
Does the study use an experimental or an
observational design?
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Dr Tarek Amin
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5. Step 3. Consider the Outcome Variable
Is the outcome being studied relevant to
clinical practice?
What criteria are used to define the
presence of disease?
Is the determination of the absence or
presence of disease accurate?
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Dr Tarek Amin
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6. Step 4. Consider the Predictor Variable
How many exposures or risk factors are being
studied?
How is the presence or absence of exposure
determined?
Is the assessment of exposure likely t be precise
and accurate?
Is there an attempt to quantify the amount or
duration of exposure?
Are biological markers of exposure used in the
study?
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Dr Tarek Amin
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7. Step 5. Consider the Methods of Analysis
Are the statistical methods employed suitable for the
types of the variables (nominal versus, ordinal versus
continuous) in the study?
Have the levels of type I and type II errors has been
discussed appropriately?
Is the sample size adequate to answer the research
question?
Have the assumptions underlying the statistical tests been
met?
Has chance been evaluated as a potential explanation of
the results?
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Dr Tarek Amin
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8. Step 6. Consider Possible source of Bias
((Systematic Error
Is the method of selection of subjects likely to
have biased results?
Is the measurement of either the exposure or the
disease likely to be biased?
Have the investigators considered whether
confounders could account for the observed
results?
In what direction would each potential bias
influence the results?
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Dr Tarek Amin
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9. Step 7. Consider the interpretation of the
.results
How large is the observed effect?
Is there evidence of a dose-response
relationship?
Are the findings consistent with laboratory
models?
Are the effect are biologically plausible?
If the findings are negative, was there
sufficient statistical power to detect an
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effect?

10. Step 8. Consider how the results of the
.study can be used in practice
Are the findings consistent with other
studies of the same questions?
Can the findings be generalized to other
human populations?
Do the findings warrant a change in
current clinical practice?
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Dr Tarek Amin
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11. Questions and Comments
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Dr Tarek Amin
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