AME Research Methods & Evidence-Based Practice 2 — Questions and Answers
Question 1: In aviation medicine research, which study design provides the strongest evidence for causality?
- Cross-sectional survey
- Randomized controlled trial (Correct answer)
- Case series report
- Expert consensus statement
Correct answer: Randomized controlled trial
Randomized controlled trials (RCTs) provide the highest level of evidence for causal relationships because randomization controls for confounding variables.
Question 2: An AME reviewing a study on hypoxia effects finds a p-value of 0.03. What does this indicate?
- The effect size is clinically significant
- There is a 3% probability the result occurred by chance under the null hypothesis (Correct answer)
- The study has a 97% power to detect the effect
- The confidence interval excludes zero
Correct answer: There is a 3% probability the result occurred by chance under the null hypothesis
A p-value of 0.03 means there is a 3% probability of obtaining results as extreme as observed if the null hypothesis were true.
Question 3: Which type of bias occurs when pilots with known cardiac conditions are more likely to be recalled and enrolled in a cardiovascular study?
- Information bias
- Recall bias
- Selection bias (Correct answer)
- Measurement bias
Correct answer: Selection bias
Selection bias occurs when the study sample is not representative of the target population due to systematic differences in who is included.
Question 4: A systematic review of aviation fatigue studies pools data from 12 individual studies. What statistical method is used to combine these results?
- Logistic regression
- Meta-analysis (Correct answer)
- Analysis of variance (ANOVA)
- Survival analysis
Correct answer: Meta-analysis
Meta-analysis is the statistical technique used in systematic reviews to quantitatively combine results from multiple independent studies.
Question 5: When evaluating aeromedical standards, which evidence source ranks highest in the hierarchy of evidence?
- Expert opinion from senior AMEs
- Single well-designed cohort study
- Systematic review of RCTs (Correct answer)
- Case-control study
Correct answer: Systematic review of RCTs
Systematic reviews (and meta-analyses) of randomized controlled trials sit at the top of the evidence hierarchy.
Question 6: An AME reads that a medication increases crash risk with an odds ratio (OR) of 2.5 (95% CI: 1.1–5.7). What can be correctly concluded?
- The medication doubles the absolute risk of a crash
- The association is statistically significant at the 0.05 level (Correct answer)
- The study had insufficient power
- The result is not clinically meaningful
Correct answer: The association is statistically significant at the 0.05 level
Since the 95% confidence interval (1.1–5.7) does not include 1.0, the result is statistically significant at the α=0.05 level.
Question 7: Which of the following best describes the concept of 'number needed to treat' (NNT) in aviation medicine research?
- The average number of patients in a clinical trial
- The number of patients who must receive treatment for one additional patient to benefit (Correct answer)
- The minimum sample size required for statistical significance
- The number of treatment arms in a study
Correct answer: The number of patients who must receive treatment for one additional patient to benefit
NNT is the reciprocal of absolute risk reduction and represents how many patients must be treated to prevent one adverse outcome.
AME Research Methods & Evidence-Based Practice 2
In aviation medicine research, which study design provides the strongest evidence for causality?