Investigations require that detectives interpret what evidence tells them about the probability that a suspect committed a crime. Unfortunately, a large body of research suggests that people are generally unable to accurately assess what a specific element of information tells them about the likelihood of an outcome. Bayes’ Theorem, however, can be used to overcome this difficulty. This article explores the use of Bayes’ Theorem to assess the question, “What does evidence tell us about the probability that someone is guilty?” A variety of analyses are presented, the results of which are not always intuitive. Policy implications are discussed.
Blair, J.P. ( 2005). A test of the unusual false confession perspective using cases of proven false confessions. Criminal Law Bulletin , 41, 127-144.
2.
Blair, J.P. ( 2007). The roles of interrogation, perception, and individual differences in producing compliant false confessions. Psychology Crime and Law, 13, 173-186.
3.
Boyce, M., Lindsay, S., & Brimacombe, E. (2008). Investigating investigators: Examining the impact of eyewitness evidence on student investigators. Law and Human Behavior, 32, 439-453.
4.
Brinegar v. U.S., 338 U.S. 160 (1949).
5.
Cassell, P.G. ( 1998). Protecting the innocent from false confessions and lost confessions and from Miranda. Journal of Criminal Law and Criminology, 88, 497-556.
6.
Cassell, P.G. ( 1999). The guilty and the "innocent": An examination of alleged cases of wrongful conviction from false confessions. Harvard Journal of Law and Public Policy, 22, 523-603.
7.
Cassell, P.G., & Hayman, B.S. ( 1996). Police interrogation in the 1990s: An empirical study of the effects of Miranda. UCLA Law Review, 43, 839-931.
8.
Dror, I.E., & Rosenthal, R. ( 2008). Meta-analytically quantifying the reliability and biasability of forensic experts. Journal of Forensic Sciences , 53, 900-903.
9.
Eck, J.E. ( 1983). Solving crimes: The investigation of burglary and robbery . Washington, DC: Police Executive Research Forum.
10.
Gudjonsson, G.H. ( 1992). The psychology of interrogations, confessions, and testimony . New York: John Wiley.
11.
Gudjonsson, G.H., & Sigurdsson, J.F. (1994). How frequently do false confessions occur? An empirical study among prison inmates. Psychology, Crime and Law, 1, 21-26.
12.
Huff, C.R. ( 2002). Wrongful conviction and public policy: The American Society of Criminology 2001 Presidential address. Criminology , 40, 1-18.
13.
lllinois v. Gates, 462 U.S. 213 (1983).
14.
Kahneman, D., Slovic, P. , & Tversky, A. (Eds.). (1982). Judgment under uncertainty: Heuristics and biases . Cambridge, UK: Cambridge University Press.
15.
Klockars, C. B., & Mastrofski, S. D. (Eds.). (1991). Thinking about police: Contemporary readings (2nd ed.). New York, NY: McGraw-Hill.
16.
Kuykendall, J. ( 1982). The criminal investigative process: Toward a conceptual framework. Journal of Criminal Justice, 10, 131-145.
17.
Leo, R.A. ( 2001). False confessions: Causes, consequences, and solutions . In S. D. Westervelt & J. A. Humphrey (Eds.), Wrongly convicted: Perspectives on failed justice (pp. 36-54). New Brunswick, NJ: Rutgers University Press.
18.
Mecklenburg, S.H. ( 2006). Report to the legislature of the state of Illinois: The Illinois pilot program on sequential double-blind identification procedures . Springfield, IL: Illinois State Police.
19.
NIJ Special Report. (2003). Eyewitness evidence: A trainer’s manual for law enforcement (NIJ Publication No. NCJ-188678). Washington, DC: U.S. Government Printing Office.
20.
Peterson, J.L., & Markham, P.N. ( 1995). Crime laboratory proficiency testing results 1978-1991. II: Resolving questions of common origin. Journal of Forensic Science, 40, 1009-1029.
21.
Robertson, B., & Vignaux, G.A. ( 1995). Interpreting evidence: Evaluating forensic evidence in the courtroom. Chichester, UK: Wiley.
22.
Rossmo, D.K. ( 2004). Geographic profiling as problem solving for serial crime . In Q. C. Thurman & J. D. Jamieson (Eds.), Police problem solving (pp. 121-131). Cincinnati, OH: Anderson Publishing.
Sanders, W. ( 1977). Detective work. New York: Free Press.
25.
Sigurdsson, J.F., & Gudjonsson, G.H. (1996). The psychological characteristics of ‘false confessors’. A study among Icelandic prison inmates and juvenile offenders. Personality and Individual Differences , 20, 321-329.
26.
Simon, R.J. ( 1969). Judges’ translations of burdens of proof into statements of probability. Trial Lawyers’ Guide , 38, 103-114.
27.
Tversky, A., & Kahneman, D. ( 1973). Availability: A heuristic for judging frequency and probability . Cognitive Psychology, 5, 207-232.
28.
Wells, G.L., & Loftus, E.F. ( 2003). Eyewitness memory for people and events. In A. M. Goldstein & I. B. Weiner (Eds.), Comprehensive handbook of psychology, Forensic psychology (Vol. 11, pp. 149-160). New York: John Wiley.
