Table 1.
Existing approaches to medicolegal causal analysis
| No. | Approach | Category | Application | Example | Strengths | Weaknesses |
|---|---|---|---|---|---|---|
| 1. | Intuitive approach (i.e. scientific common-sense) | Intuitive | Simple cases where the causal relationship “makes sense” based on fundamental scientific principles | Death following a gunshot wound to the head | Practical, does not need exceptional/additional resources | Not suitable for more complex cases where the causal relationship is not as readily apparent |
| 2. | Categorical intuitive deduction (i.e. the Sherlock Holmes style or educated guess) | Intuitive | Cases where there is only one plausible cause at the same time | Death following ingestion of insecticides in a previously healthy person with no signs of trauma | Impressive expert witness testimony | Not suitable for more complex cases where there is more than one plausible cause, requires a lot of professional experience, potentially misleading |
| 3. | Hill’s viewpoints [19] | Intuitive-probabilistic | Cases with sufficient epidemiologic evidence and literature to assess competing causal hypotheses | Post-traumatic headache in a sexual-assault victim | Check-list-like criteria to guide causal inference | Temporal sequence is the only real “causal criterion” [76], the meaning or value of the other criteria can be unclear [77] |
| 4. | The American Medical Association (AMA) Guides to the Evaluation of Disease and Injury Causation [6, 61] | Intuitive-probabilistic | Primarily cases of injury with multiple plausible causes and work-related conditions | Lower back-pain in a factory worker who stands all-day | Provide elements that may be used for a systematic step-by-step causal analysis, primarily to assess work-relatedness | Lengthy and complicated process, does not produce a PC/quantification of the level of certainty |
| 5. | Forcier-Lacerte medicolegal causal analysis model [60] | Intuitive-probabilistic | Primarily cases of injury with multiple plausible causes and cases related to insurance claims | An elderly woman with severe osteoporosis who sustains a slip-and-fall resulting in several fractured ribs | Provide elements that may be used for a systematic step-by-step causal analysis, categorizes possible causes into (1) the accident, (2) preexisting health status, and (3) intervening event. | Lengthy and complicated process, does not produce a PC/quantification of the level of certainty |
| 6. | The epidemiology-based approach by Siegerink et al. [30] | Probabilistic | Civil litigations or cases of tort, where the issue is primarily about the proportional liability of multiple plausible causes | The risk of lung cancer in a factory worker exposed to asbestos, who is also a heavy smoker with a family history of lung cancer | Fits both the sufficient cause model and the counterfactual model, offers proportional liability for each component cause (i.e. the unlawful act plus other possible factors) | Could overestimate the number of components of the sufficient cause, leading to an underestimation of liability, all components are considered as of equal importance, while from a legal perspective some causes may be more important than others (e.g. unlawful act vs genetics) |
| 7. | The 3-step medicolegal causation approach by Freeman [8] | Probabilistic | Cases of injuries with multiple plausible causes that do not require a high degree of energy, preexisting conditions which only become symptomatic after relatively minor trauma, or conditions with an insidious symptom onset | An elderly woman with shoulder pain after a minimal-damage rear-impact collision | Practicable, systematic, fits the standards of both medical and legal practice by establishing (1) plausibility, (2) temporality, and (3) the absence of a more probable alternative explanation (differential etiology) | Requires sufficient epidemiologic data and comprehension of epidemiologic methods to compare risks of differential etiologies |
| 8. | The forensic epidemiology approach [62, 63] | Probabilistic | Highly complex cases with multiple plausible causes | Peripartum cardiomyopathy in a young woman following exposure to doxorubicin | Systematic, provides a scientifically valid and verifiable quantification of probability in the form of a comparative risk ratio (CRR) and a probability of causation (PC), results are suitable for presentation in a court of law | Uses epidemiologic principles, methods, and data to formulate a probability, the analyses and calculations can be quite complicated, might not be suitable for day-to-day forensic medical practice |