Critical appraisal of published medical research (2)

04/09/23 Dr Tarek Amin 1

Critical Appraisal of Published Medical Research

Dr. Tarek Tawfik


Consider the research hypothesis

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

Consider the utility of the results

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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?


Step 2. Consider the Study DesignIs 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?


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?


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?


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?


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?


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 effect?


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?


Questions and Comments

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Critical appraisal of published medical research (2)