GPT STUDY GUIDE Flashcards
(100 cards)
What is a cohort study?
A study that follows groups over time to observe outcomes; can be prospective or retrospective.
What are advantages of cohort studies?
Can establish temporal relationships, calculate incidence rates.
What are disadvantages of cohort studies?
Time-consuming, expensive, potential for loss to follow-up.
What measures are used in cohort studies?
Relative risk, incidence rates, attributable risk.
What does a cross-sectional study measure?
Prevalence.
What does a case-control study measure?
Odds ratios.
What does a cohort study measure?
Incidence and relative risk.
What do RCTs measure?
Efficacy and effectiveness measures.
What is absolute risk?
Actual probability of an event occurring, e.g., 5 in 100.
What is relative risk?
Ratio comparing risks between groups.
How is absolute risk calculated?
It is equivalent to the incidence rate.
Why might high relative risk not be clinically meaningful?
If absolute risk is low, even a high relative risk may have little practical impact.
What is sensitivity?
Proportion of true positives correctly identified: TP / (TP + FN).
What is specificity?
Proportion of true negatives correctly identified: TN / (TN + FP).
What is positive predictive value (PPV)?
TP / (TP + FP).
What is negative predictive value (NPV)?
TN / (TN + FN).
How does prevalence affect predictive values?
PPV increases with prevalence, NPV decreases.
What is the formula for odds ratio (OR)?
(a × d) / (b × c) using a 2×2 table.
What does OR = 1 mean?
No association between exposure and outcome.
What does OR > 1 mean?
Increased odds of outcome with exposure.
What does OR < 1 mean?
Decreased odds of outcome with exposure.
What is a p-value?
Probability of observing results if the null hypothesis is true.
What p-value is typically considered statistically significant?
p < 0.05.
What are limitations of p-values?
They do not indicate effect size or clinical significance.