Document Category: Profiling Evidence

This motion argues for the exclusion of opinion testimony by medical examiners on the manner of death in a homicide trial under both the rules of evidence and the Sixth Amendment jury trial right. It explains that medical examiners speculate as to the “manner” of death based on extraneous information provided to them, notes that these determinations are not based on science, and emphasizes that there is “no standardized or validated system” for making these judgments (pages 18-23). The motion also cites cognitive science in support of the claim that biases, including racial biases, can shape these “manner of death” determinations (pages 23-24). Attached to the motion are (1) transcripts of interviews with two medical examiners, exposing the problems with manner of death determinations; (2) an expert report and law review article detailing the cognitive science problems with these determinations; (3) the non-scientific manual used to instruct medical examiners on how to make these determinations; and (4) a letter signed by 86 forensic pathologists and death investigators about judicial misuse of manner of death determinations.

This motion relies on the Federal Rules of Evidence to argue for exclusion of police testimony about the behavior of drug traffickers. Pages 13-14 rely on social science to argue that users of fentanyl, methamphetamine, and cocaine consume large quantities of each of those drugs daily to support their habit such that courts cannot infer distribution from larger amounts. Pages 15-16 collect national data to refute the suggestion that drug traffickers typically possess firearms.

This motion relies on federal rules of evidence and Daubert to argue that a physician should not be permitted to testify that a person died from an oxycodone overdose when there are alternative potential causes of death – such as cardiac arrhythmia – that have not be properly eliminated. More generally, the motion explains when doctors who rely on differential diagnosis – the process of identifying the cause of a medical problem by eliminating likely causes until the most probable one is isolated – are conducting a reliable, medical analysis versus when their analyses are compromised by cognitive biases. The social science collected in this motion would be useful to defenders challenging the validity of any causal conclusion physicians reach.

Pages 4-6 explain the differential diagnosis process and how it can lead physicians to make unreliable conclusions about cause of death.  Pages 6-17 discuss how cognitive biases like confirmation bias, role effects, the availability heuristic, and the representativeness error can infect differential diagnoses.  Pages 17-20 talk about when differential diagnoses are unreliable due to a physician’s failure to properly rule in certain causes and rule out potential alternatives.  Pages 20-24 draw analogies to the forensic sciences and argue that the physician in this case could testify that there was oxycodone in the patient’s system but should not have been able to opine with certainty that it caused the patient’s death.  Pages 24-28 explain why the doctor’s ultimate opinion invaded the province of and was unhelpful to the jury.

Summarizes research on accuracy of “criminal profiling” evidence over forty years, concluding profilers are no “better than bartenders at predicting the traits and features of offenders.” Also provides an overview of cases nationwide excluding criminal profiling evidence and finding that its major premise is faulty and essentially propensity evidence.