Trial by Statistics: Is a High Probability of Guilt Enough to Convict?

Mind ◽  
2018 ◽  
Vol 128 (512) ◽  
pp. 1045-1084 ◽  
Author(s):  
Marcello Di Bello
Keyword(s):  
Utility Maximization ◽  
High Probability ◽  
Eyewitness Testimony ◽  
Criminal Trials ◽  
Dna Evidence ◽  
Noteworthy Feature ◽  
Expected Utility Maximization ◽  
Theoretic Argument ◽  
Fairness Constraints ◽  
Civil Trials

Abstract Suppose one hundred prisoners are in a yard under the supervision of a guard, and at some point, ninety-nine of them collectively kill the guard. If, after the fact, a prisoner is picked at random and tried, the probability of his guilt is 99%. But despite the high probability, the statistical chances, by themselves, seem insufficient to justify a conviction. The question is why. Two arguments are offered. The first, decision-theoretic argument shows that a conviction solely based on the statistics in the prisoner scenario is unacceptable so long as the goal of expected utility maximization is combined with fairness constraints. The second, risk-based argument shows that a conviction solely based on the statistics in the prisoner scenario lets the risk of mistaken conviction surge potentially too high. The same, by contrast, cannot be said of convictions solely based on DNA evidence or eyewitness testimony. A noteworthy feature of the two arguments in the paper is that they are not confined to criminal trials and can in fact be extended to civil trials.

Decision-theoretic and risk-based approaches to naked statistical evidence: some consequences and challenges

2020 ◽  
Vol 19 (1) ◽  
pp. 67-83 ◽  
Author(s):  
Rafal Urbaniak ◽  
Alicja Kowalewska ◽  
Pavel Janda ◽  
Patryk Dziurosz-Serafinowicz
Keyword(s):  
Likelihood Ratio ◽  
Expected Utility ◽  
Utility Maximization ◽  
Empirical Studies ◽  
Eyewitness Testimony ◽  
Statistical Evidence ◽  
Similar Extent ◽  
Expected Utility Maximization ◽  
Fairness Constraints ◽  
Narrow Context

Abstract In the debate about the legal value of naked statistical evidence, Di Bello argues that (1) the likelihood ratio of such evidence is unknown, (2) the decision-theoretic considerations indicate that a conviction based on such evidence is unacceptable when expected utility maximization is combined with fairness constraints, and (3) the risk of mistaken conviction based on such evidence cannot be evaluated and is potentially too high. We argue that Di Bello’s argument for (1) works in a rather narrow context, and that (1) is not exactly in line with the way expert witnesses are required to formulate their opinions. Consequently, Di Bello’s argument for (2), which assumes (1), does not apply uniformly to all convictions based on naked evidence. Moreover, if Di Bello’s analysis is correct, it applies also to eyewitness testimony, given empirical results about its quality, and so the distinctions drawn by DiBello cut across the distinction between naked statistical evidence and other types of evidence. Finally, if we weaken the rather strong requirement of precise measurability of the risk of mistaken conviction, to the availability of reasonable but imprecise and fallible estimates, many field and empirical studies show that often the risk of mistaken conviction based on naked statistical evidence can be estimated to a similar extent as the risk of mistaken conviction based on any other sort of evidence.

Thucydides as a Prospect Theorist

2014 ◽  
Vol 31 (2) ◽  
pp. 206-232 ◽  
Author(s):  
Josiah Ober ◽  
Tomer J. Perry
Keyword(s):  
Utility Maximization ◽  
High Probability ◽  
Decision Makers ◽  
The Political ◽  
Risk Seeking ◽  
Political Effects ◽  
The Face ◽  
Expected Utility Maximization ◽  
Excessive Risk ◽  
Small Probabilities

Opposing the tendency to read Thucydides as a strong realist, committed to a theory of behaviour that assumes rationality as expected utility maximization, Ned Lebow and Clifford Orwin (among others) emphasize Thucydides’ attentiveness to deviations from rationality by individuals and states. This paper argues that Thucydides grasped the principles underlying contemporary prospect theory, which explains why people over-weight small probabilities and under-weight near certain ones. Thucydides offers salient examples of excessive risk-aversion in the face of probable gains and excessive risk-seeking by decision-makers faced with high probability losses. Thucydides suggests that in a democracy, leaders’ rhetoric can limit or exacerbate the political effects of bias in risk assessment.

scholarly journals Reasoning about social preferences with uncertain beliefs

2021 ◽  
Author(s):  
isaac davis ◽  
Ryan W. Carlson ◽  
Yarrow Dunham ◽  
Julian Jara-Ettinger
Keyword(s):  
Expected Utility ◽  
Utility Maximization ◽  
Social Preference ◽  
Social Preferences ◽  
Social Judgments ◽  
Social Agents ◽  
Preference Reasoning ◽  
The Face ◽  
Expected Utility Maximization ◽  
Social Uncertainty

We propose a computational model of social preference judgments that accounts for the degree of an agents’ uncertainty about the preferences of others. Underlying this model is the principle that, in the face of social uncertainty, people interpret social agents’ behavior under an assumption of expected utility maximization. We evaluate our model in two experiments which each test a different kind of social preference reasoning: predicting social choices given information about social preferences, and inferring social preferences after observing social choices. The results support our model and highlight how un- certainty influences our social judgments.

Specialist versus Generalist Decision Making

2018 ◽  
Author(s):  
Armin W. Schulz
Keyword(s):  
Decision Making ◽  
Expected Utility ◽  
Utility Maximization ◽  
Decision Rules ◽  
Mental States ◽  
Vast Array ◽  
Expected Utility Maximization

A number of scholars argue that human and animal decision making, at least to the extent that it is driven by representational mental states, should be seen to be the result of the application of a vast array of highly specialized decision rules. By contrast, other scholars argue that we should see human and animal representational decision making as the result of the application of a handful general principles—such as expected utility maximization—to a number of specific instances. This chapter shows that, using the results of chapters 5 and 6, it becomes possible to move this dispute forwards: the account of the evolution of conative representational decision making defended in chapter 6 together with the account of the evolution of cognitive representational decision making defended in chapter 5, makes clear that both sides of this dispute contain important insights, and that it is possible to put this entire dispute on a clearer and more precise foundation. Specifically, I show that differentially general decision rules are differentially adaptive in different circumstances: certain particular circumstances favor specialized decision making, and certain other circumstances favor more generalist decision making.

8. Opinion evidence

2018 ◽  
Author(s):  
Maureen Spencer ◽  
John Spencer
Keyword(s):  
Expert Opinion ◽  
Expert Witness ◽  
Common Law ◽  
Expert Evidence ◽  
High Quality ◽  
Criminal Trials ◽  
Questions And Answers ◽  
Flow Charts ◽  
Scientific Expertise ◽  
Civil Trials

The Concentrate Questions and Answers series offers the best preparation for tackling exam questions. Each book includes typical questions, bullet-pointed answer plans and suggested answers, author commentary and diagrams and flow charts. This chapter explores an area of evidence law dominated by expert witness evidence and the extent to which flawed testimony leads to miscarriages of justice. Expert evidence is now commonplace in criminal and civil trials, and the courts and Parliament have developed procedures to ensure that it is of high quality. These are an eclectic mix of common law and statute and their development reflects the importance of scientific expertise. It is necessary to be familiar with the differences between expert and non-expert opinion evidence and on when and in what circumstances both types are admissible and questions that can be asked of the expert whilst giving evidence. The approach depends on whether the question relates to civil or criminal trials

Conclusion

2020 ◽  
pp. 248-250
Author(s):  
Paul Weirich
Keyword(s):  
Expected Utility ◽  
Utility Maximization ◽  
Risk Principle ◽  
Expected Utility Maximization ◽  
The Mean ◽  
Mean Risk

Recognizing that an act’s risk is a consequence of the act yields a version of expected-utility maximization that does not need adjustments for risk in addition to the probabilities and utilities of possible outcomes. This treatment of an act’s risk justifies the expected-utility principle, and the mean-risk principle, for evaluation of an act. Rational attitudes to risks explain the rationality of acting in accord with the principles. They ground the separability relations that support the principles. The expected-utility principle justifies a substantive, and not just a representational, version of the decision principle of expected-utility maximization. Consequently, the principle governs a single choice and not just sets of choices. It demands more than consistency of the choices in a set. It demands that each choice follow the agent’s preferences, and these preferences explain the rationality of a choice that complies with the principle.

Sign in / Sign up

Export Citation Format

Share Document