title: On the likelihood of "encapsulating all uncertainty".
abstract: The assignment of personal probabilities to form a forensic practitioner's likelihood ratio is a mental operation subject to all the frailties of human memory, perception and judgment. While we agree that beliefs expressed as coherent probabilities are neither 'right' nor 'wrong' we argue that debate over this fact obscures both the requirement for and consideration of the 'helpfulness' of practitioner's opinions. We also question the extent to which a likelihood ratio based on personal probabilities can realistically be expected to 'encapsulate all uncertainty'. Courts cannot rigorously assess a forensic practitioner's bare assertions of belief regarding evidential strength. At a minimum, information regarding the uncertainty both within and between the opinions of practitioners is required.
authors.affiliation: School of Psychology, The University of New South Wales. Electronic address: k.martire@unsw.edu.au.
authors.forename: Kristy A
authors.initials: KA
authors.lastname: Martire
authors.affiliation: Faculty of Law, The University of New South Wales.
authors.forename: Gary
authors.initials: G
authors.lastname: Edmond
authors.affiliation: School of Psychology, The University of New South Wales.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Navarro
authors.affiliation: School of Psychology, The University of New South Wales.
authors.forename: Ben R
authors.initials: BR
authors.lastname: Newell
mesh_terms: D044707:Forensic Sciences / Q000331:legislation & jurisprudence*; D006801:Humans; D016013:Likelihood Functions; D035501:Uncertainty