Biostatistics & Ethics
Core Formulas
| Concept | Formula |
|---|
| Sensitivity | TP / (TP + FN) |
| Specificity | TN / (TN + FP) |
| PPV | TP / (TP + FP) |
| NPV | TN / (TN + FN) |
| ARR | Control event rate − experimental event rate |
| NNT | 1 / ARR |
| NNH | 1 / absolute risk increase |
Ethics Defaults
- Assess decision-making capacity first.
- Respect capacitated refusal, even if medically unwise.
- For incapacitated patients: advance directive → healthcare proxy → substituted judgment → best-interest standard.
- Break confidentiality only for clear legal/public safety exceptions.