Determining the Base Rate for Guilt
(2018) In Law, Probability and Risk 17(1). p.1528 Abstract
 A Bayesian assessment of the probability that the defendant in a criminal trial is guilty depends on the presumed base rate for guilt and the estimated likelihoods of the evidence. This article explores how the base rate shall be determined. Bayesian scholars have recommended a base rate of 1/N, where N is the number of ‘possible perpetrators’, but it is unclear how the reference class of possible perpetrators shall be defined. Several solutions are explored, and it is demonstrated that each solution leads to serious sacrifices in some fundamental principle of criminal justice. Some solutions lead to arbitrary assessments, or assessments that deviate from the facts. Other solutions fail to uphold an acceptable ratio between wrongful... (More)
 A Bayesian assessment of the probability that the defendant in a criminal trial is guilty depends on the presumed base rate for guilt and the estimated likelihoods of the evidence. This article explores how the base rate shall be determined. Bayesian scholars have recommended a base rate of 1/N, where N is the number of ‘possible perpetrators’, but it is unclear how the reference class of possible perpetrators shall be defined. Several solutions are explored, and it is demonstrated that each solution leads to serious sacrifices in some fundamental principle of criminal justice. Some solutions lead to arbitrary assessments, or assessments that deviate from the facts. Other solutions fail to uphold an acceptable ratio between wrongful acquittals and wrongful convictions. (Less)
 Abstract (Swedish)
 A Bayesian assessment of the probability that the defendant in a criminal trial is guilty depends on the presumed base rate for guilt and the estimated likelihoods of the evidence. This article explores how the base rate shall be determined. Bayesian scholars have recommended a base rate of 1/N, where N is the number of ‘possible perpetrators’, but it is unclear how the reference class of possible perpetrators shall be defined. Several solutions are explored, and it is demonstrated that each solution leads to serious sacrifices in some fundamental principle of criminal justice. Some solutions lead to arbitrary assessments, or assessments that deviate from the facts. Other solutions fail to uphold an acceptable ratio between wrongful... (More)
 A Bayesian assessment of the probability that the defendant in a criminal trial is guilty depends on the presumed base rate for guilt and the estimated likelihoods of the evidence. This article explores how the base rate shall be determined. Bayesian scholars have recommended a base rate of 1/N, where N is the number of ‘possible perpetrators’, but it is unclear how the reference class of possible perpetrators shall be defined. Several solutions are explored, and it is demonstrated that each solution leads to serious sacrifices in some fundamental principle of criminal justice. Some solutions lead to arbitrary assessments, or assessments that deviate from the facts. Other solutions fail to uphold an acceptable ratio between wrongful acquittals and wrongful convictions. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/3ed9c71f34c744029ce2e52ac864d1ac
 author
 Dahlman, Christian ^{LU}
 organization
 publishing date
 20180301
 type
 Contribution to journal
 publication status
 published
 subject
 keywords
 Law, Jurisprudence, Rättsvetenskap, Allmän rättslära
 in
 Law, Probability and Risk
 volume
 17
 issue
 1
 pages
 15  28
 publisher
 Oxford University Press
 external identifiers

 scopus:85043454246
 ISSN
 1470840X
 DOI
 doi:10.1093/lpr/mgx009
 language
 English
 LU publication?
 yes
 id
 3ed9c71f34c744029ce2e52ac864d1ac
 date added to LUP
 20171218 18:00:05
 date last changed
 20200526 04:32:41
@article{3ed9c71f34c744029ce2e52ac864d1ac, abstract = {A Bayesian assessment of the probability that the defendant in a criminal trial is guilty depends on the presumed base rate for guilt and the estimated likelihoods of the evidence. This article explores how the base rate shall be determined. Bayesian scholars have recommended a base rate of 1/N, where N is the number of ‘possible perpetrators’, but it is unclear how the reference class of possible perpetrators shall be defined. Several solutions are explored, and it is demonstrated that each solution leads to serious sacrifices in some fundamental principle of criminal justice. Some solutions lead to arbitrary assessments, or assessments that deviate from the facts. Other solutions fail to uphold an acceptable ratio between wrongful acquittals and wrongful convictions.}, author = {Dahlman, Christian}, issn = {1470840X}, language = {eng}, month = {03}, number = {1}, pages = {1528}, publisher = {Oxford University Press}, series = {Law, Probability and Risk}, title = {Determining the Base Rate for Guilt}, url = {http://dx.doi.org/doi:10.1093/lpr/mgx009}, doi = {doi:10.1093/lpr/mgx009}, volume = {17}, year = {2018}, }