Step 1: Collate. Organize the standard of care and the medical intervention into 10 corresponding phases with a respective duty.
Step 2: Compare. Compare corresponding phases using three measures:
- Background risk: Each phase in the standard of care. It is the probability that the complication is a random error-of-nature.
- Relative risk: Risk of harm for each phase in the medical intervention. If there is no difference between a phase in standard of care and the corresponding phase in medical intervention, the relative risk is one. If there is a difference, the relative risk is greater than one. The yardstick is the “threshold-risk ratio,” 100 percent divided by background risk. Rationale when greater than one: a calculated risk. Rationale when equal to the threshold-risk ratio: no breach of duty. Rationale when greater than the threshold-risk ratio (rare): res ipsa loquitur.
- Incident risk: Background risk x relative risk = phase of the medical intervention.
For each of the 10 phases below, weigh standard of care (background risk) against medical intervention, give the relative risk and its rationale, and calculate incident risk as relative risk x background risk:
- 1. The presentation phase: The duty is to perform a history and physical and identify all risks and preexisting conditions.
- 2. The investigation phase: The duty is a complete medical work-up (labs, EKG, imaging studies, consultations, previous medical records, etc.).
- 3. The interpretation phase: The duty is to understand the relevance of all results.
- 4. The diagnostic phase: The duty is to determine final diagnosis and prognosis.
- 5. The deliberation phase: The duty is to determine alternative medical interventions.
- 6. The informed consent phase: The duty is to disclose risks, benefits, and complications of these alternatives, to the patient and/or to the patient’s representative.
- 7. The selection phase: The duty is to select the safest, most effective management from among these choices with the knowledge and approval of the patient and/or the representative.
- 8. The technical phase: The duty is to exercise due caution in each detail and to respond to unforeseen circumstances.
- 9. The recovery phase: The duty is to appropriately respond to progress and to complications.
- 10. The discharge phase: The duty is to determine that the patient has recovered sufficiently from this medical condition to conclude management and/or to arrange follow-ups.
Step 3: Calculate. Prove whether the medical intervention comports with or departs from the standard of care using the single-sample t-test.
- The null hypothesis (Ho): “There is no statistically significant difference between the background risk, representing the standard of care, and the test sample of 10 incident risks, representing the medical intervention. The complication is an error-of-nature.”
- The alternate hypothesis (Ha): “There is a statistically significant difference. The complication is a medical error.”
- The level of significance: Alpha (α), either 0.5 (the sine qua non in law) or 0.05 (the sine qua non in science).
- The test sample: Incident risks for 10 phases of medical intervention.
- The population mean: Background risk.
- Tail: One or upper.
- The p value: If the p value is greater than alpha, the difference is not statistically significant. The null hypothesis is retained. Otherwise, it is rejected.
Step 4: Certify. Prepare and notarize a report.
The certified report
- Injury is the complication in question.
- Duty is any medical intervention with a p value greater than alpha.
- Breach of duty is any medical intervention with a p value equal to or less than alpha.
- Proximate cause is any medical intervention that causes an injury. It is represented by the p value.
- The scientific method and hypothesis testing are generally accepted norms of critical thinking.
- CCC+C is peer review and is published in scientific literature.
- The medical expert is qualified. CV is attached.
- Two error rates: There are type-I and type-II errors. When type-I error is 5 percent, type-II error is 20 percent. When type-I error is 50 percent, type-II error is 0.65 percent.
- Four biases: Selection bias, avoidance bias, confirmation bias, heuristic bias. When the null hypothesis is retained, selection bias = type-I error; avoidance bias = type-II error; confirmation bias = alpha – p value; and heuristic bias is either 0 or 100 percent. When the null hypothesis is rejected, selection bias = 100 percent – type-I error; avoidance bias = 100 percent – type-II error; confirmation bias = alpha – p value; and heuristic bias is either 0 or 100 percent.
- Merit: Maximum reliability (100 percent) – (the average of selection, avoidance, confirmation, and heuristic biases).
Howard Smith is an obstetrics-gynecology physician.
