Epidemiology Flashcards
Which study design is the most scientifically sound and the best measure of exposure?
Clinical trial
Which study design is the most accurate observation study and a good measure of exposure?
Cohort study
Which study design can study rare diseases and is relatively less expensive/fast?
Case-control
Which study design is the fastest and least expensive and measures multiple exposures and outcomes?
Cross-sectional
Which study design is time consuming and the most expensive?
Cohort study
Which study design causes possible time-order confusion and possible error recalling exposures?
Case-control
Which study design causes possible time-order confusion, the least confidence in findings, and measurement bias?
Cross-sectional
Which study design is time consuming, not generalizable, unethical for harmful exposures, and most expensive?
Clinical trial
What happens to incidence and prevalence if a new effective treatment is initiated?
Incidence stays the same, prevalence decreases
What happens to incidence and prevalence if a new effective vaccine gains widespread use?
Incidence decreases, prevalence decreases
What happens to incidence and prevalence if number of persons dying from the conditions decreases?
Incidence stays the same, prevalence increases
Case fatality rate equation
Number of deaths due to disease/number of cases of a disease
Proportionate mortality rate equation
Number of deaths due to disease/total deaths in the population
Attributable risk equation
Incidence rate among exposed - incidence rate among unexposed
Relative risk equation
Incidence rate among treated / incidence rate among non-treated
Attributable risk percent equation
AR / incidence rate among treated
Number needed to treat
1 / attributable risk
Relative risk equation
[a/(a+b)] / [c/(c+d)]
Odds ratio equation
ad/bc
T/F: For a rare disease, odds ratio is a good measure of the relative risk.
True
Interpret a RR of 5.0
50% chance of developing a disease if exposed
P value of 0.05. What does this mean?
There is a 5% chance that the results were just do to chance
Limitations of p-values
dependent on sample size
larger effect sizes more likely to produce significant sample size
only assess the null hypothesis, not the alternative hypothesis
tells us about statistical significance but nothing about magnitude of effect
T/F: P-values more likely to be statistically significant for larger effects
True.