Case control study
- odds ratio
Clinical trial: Phase 1
- “Is it safe?” Assesses safety, toxicity, and pharmacokinetics.
Clinical trial: Phase 2
- “Does it work?” Assesses treatment efficacy, optimal dosing, and adverse effects.
Clinical trial: Phase 3
Clinical trial: Phase 4
-Postmarketing surveillance trial of patients after
approval.
-“Can it stay?” Detects rare or long-term adverse effects. Can result in a drug being withdrawn from market.
Vaccine
-whats reduced, incidence or prevalence?
Both
Precision
Accuracy
- The trueness of test measurements. The absence of systematic error or bias in a test.
Internal validity:
How well the conclusion corresponds to the real situation in the sample population.
Berkson bias
- A study looking only at inpatients.
Hawthorne effect
- Groups who know they’re being studied behave differently than they would otherwise.
Pygmalion effect
-aka?
-Observer-expectancy bias
Lead-time bias
-what is it?
Early detection confused w/inc. survival.
-seen w/improved screening techniques.
Lead-time bias
-how do you reduce this bias?
Measure “back-end” survival (adjust survival according to
the severity of disease at the time of diagnosis).
Crossover studies
-what is it?
-subjects act as their own controls.
Matching
-what is it?
standard error of mean (SEM)
-relationship w/sample size
As (n) increases, SEM decreases.
Skew:
-define it
Think of normal bell curve but you grab one side and pull
it a little. If you pull it to the right, its positive skew. And
in ABC order, you drag the Mean, Median, and Mode along with it.
Power of a study
Chi-square (χ²)
-Example: comparing the percentage of members of 3 different ethnic groups who have essential hypertension.
Coefficient of determination =
- r = Pearson correlation coefficient
Disease prevention
-mnemonic?
PST:
Disease prevention: primary
-Prevent disease occurrence (e.g., HPV vaccination).
Disease prevention: tertiary
-Treatment to reduce disability from disease (e.g., chemotherapy).