Forensic Epidemiology: A Systematic Approach To Probabilistic Determinations In Disputed Matters

Authors:

Michael D. Freeman PhD, MPH, DC (Adjunct Associate Professor of Forensic Medicine and Epidemiology, Clinical Associate Professor)

Institute of Forensic Medicine, Faculty of Health Sciences, University of Aarhus, 205 Liberty Street, Suite B, Salem, OR 97301, USA
and Department of Public Health and Preventive Medicine, Oregon Health and Science University School of Medicine, USA

Annette M. Rossignol ScD (Professor)

Department of Public Health, Oregon State University, USA

Michael L. Hand PhD (Professor)

Atkinson Graduate School of Management, Willamette University, USA

 

Abstract

Forensic medicine testimony often relies upon terms of probability to enhance the strength of the testimony. Such terms must have a demonstrably reliable and accurate basis; otherwise their use is speculative, unjustified, and potentially harmful. Forensic Epidemiology is introduced as a framework from which probabilistic testimony can be assessed in settings in which it is either proffered or encountered. In this paper, common forensic uses of probability are reviewed, appropriate methods for presenting such testimony are proposed, and inappropriate uses of probability and epidemiologic concepts and data, as well as a logical fallacies commonly observed in forensic settings are presented. A previously unpublished logical fallacy, the ‘‘Prior Odds” Fallacy, is also introduced.

Conclusions

The 19th century essayist and novelist Charles DudleyWarner (1829–1900) is credited with the quote ‘‘Everyone complains about the weather but no one does anything about it”. In some ways, the quote is apropos for the widespread but unsystematic use of probability in forensic medicine, in that everyone uses it but not everyone understands it. The purpose of this paper, in which the concept and some of the applications of Forensic Epidemiology have been introduced, is to fill a void that presently exists in forensic medicine with the addition of a general heading under which the proper and improper forensic use of probability is systematically described. As demonstrated by the tragedy of the Sally Clark case, there is little doubt that the use of probability in forensic medicine is in need of standardization; there is a high potential for continued harm and injustice if nothing is done in this regard. Better and more explicit heuristics are needed to describe and implement the concepts introduced in this paper for the wide variety of circumstances encountered in forensic medicine. A few recommendations are as follows:

1)  Be alert for the language of probability or epidemiology in forensic opinions.
2)  When epidemiologic data are referenced as a basis for an opinion, evaluate the propriety of their use. Are the sample population and circumstances sufficiently similar to allow for extrapolation to the facts in the present case?
3)  When in doubt regarding causal determinations, return to the three essential elements of causation: biologic plausibility, temporality, and lack of likely alternative explanation.
4)When a clinical outcome is known, be aware of the potential for Prior Odds and other fallacies.
5) If a test or criterion is set as an evidentiary standard, determine if the Specificity, Sensitivity, and Positive Predictive Value is known or can be determined for the test or criterion. Use these tools to help determine the real utility of the test or criterion in a forensic setting.

For full a paper please see source. You can also download the PDF version medicalmisdiagnosisresearch BoxNet files.

Source:

http://www.internationalbrain.org/pdf_public/lisbon/Freeman%20Lisbon,%20Forensic%20Epidemiology.pdf