Category Archives: Expert witness

Alcohol Intoxication and Blackout

A high per­cent­age of crime is com­mit­ted when both defen­dants and vic­tims are alco­hol intox­i­cated. Forensic clin­i­cians are reg­u­larly asked to eval­u­ate men­tal states at the time of the offense for accused per­pe­tra­tors and vic­tims of alleged crime dur­ing peri­ods of alco­hol intox­i­ca­tion. In crim­i­nal pro­ceed­ings, both defen­dants and vic­tims com­monly claim that alco­hol intoxication […]

Error and bias in forensic behavioral science

A cri­sis is brew­ing in sci­en­tific psy­chol­ogy and foren­sic sci­ence. This con­cerns the over­all reli­a­bil­ity of all psy­cho­log­i­cal sci­ence (more on this later) and the qual­ity of expert evi­dence and tes­ti­mony in courts of law, regard­less of the expert’s dis­ci­pline (yes, even includ­ing the sup­pos­edly hard stuff, like DNA analy­sis). The con­sen­sus: alarm­ingly poor. This […]

Ipse Dixit, Expert witnesses, & Specialty Guidelines for Forensic Psychology

Ipse Dixit in Latin means, “he him­self said it”; It is fre­quently encoun­tered in expert tes­ti­mony. Ipse dixit is an unsup­ported state­ment that rests solely on the author­ity of the speaker. I think a bet­ter trans­la­tion is “because I said it…[it is true].” It is a con­clu­sory opin­ion with­out sup­port. Gutheil & Bursztjan (2003) articulate […]

Bias, cognitive heuristics, and forensic decision-making

The cumu­la­tive weight of 30 years of research orig­i­nat­ing in Tversky and Kaheman’s sem­i­nal 1974 descrip­tion of the men­tal short­cuts humans use when con­fronting cog­ni­tive ambi­gu­ity com­plex­ity, and Kahneman’s recent mas­ter­piece Thinking Fast, and Slow (2011, cf. Gilovich, Griffin, & Kahneman, 2002) has cre­ated a mature cog­ni­tive sci­ence of foren­sic decision-making. The find­ings are not […]

Forensic Psychology is Forensic Science.

There has been a grow­ing aware­ness, some would say cri­sis, con­cern­ing the mediocre qual­ity of expert foren­sic tes­ti­mony sub­mit­ted to the courts in the United States. This appears to be a func­tion of weak meth­ods, and a low thresh­old for judi­cial gate­keep­ing, despite clear man­dates in Rule 702 and Daubert and prog­eny on the foundations […]

Professional Ethics,“partisan allegiance,” and expert witness liability

Daniel Murrie and his col­leagues have pro­duced a series of recent stud­ies on “par­ti­san alle­giance” in foren­sic expert wit­ness work (see cita­tions below). They define par­ti­san alle­giance as the ten­dency for experts to bias their tes­ti­mony in favor of the side that calls them. They demon­strate this through inge­nious exper­i­ments with PCL-R rat­ings. The response […]

Thriving as a forensic psychologist

A nice arti­cle by William Foote PhD in APA’s Good Practice (Winter 2014) is worth a look for stu­dents who think they might be inter­ested in foren­sic psy­chol­ogy. Contrasting clin­i­cal and foren­sic psy­chol­ogy, he writes, “But the field is not for everyone…Forensic psy­chol­ogy is also much more con­fronta­tional. You’re often in an adver­sar­ial posi­tion, with […]

Assessing Homicidal Mental States at the Time of Offense IV: The 2011 Norway Massacre: Criminal responsibility analysis using the R-CRAS.

The use of foren­sic assess­ment instru­ments is a dis­tin­guish­ing fac­tor in the qual­ity of foren­sic reports (Fuger, Acklin, Nguyen, Ignacio, & Gowensmith, 2013). In insan­ity deter­mi­na­tions, the Rogers Criminal Responsibility Assessment Scales (R-CRAS, PAR, Inc.) are with­out peer as an aide to orga­niz­ing and ana­lyz­ing case data. It is a sys­tem­atic cod­ing mea­sure which permits […]

Analysis of Competing Hypotheses (ACH) — a method for de-biasing forensic decision making

I recently attended a three day work­shop on school, cam­pus, and work­place threat assess­ment and became acquainted with ACH. It is a method­ol­ogy devel­oped by the CIA and is used to con­sider evi­dence when fac­tors are com­plex or ambigu­ous. Given the many fac­tors that can influ­ence foren­sic deci­sion mak­ing, includ­ing exam­iner deci­sion thresh­olds, cost of […]

New variety of shark sighted in Hawaii waters

Readers may remem­ber my post on “Swimming with Sharks” a few months back–a set of guide­lines and admon­ish­ments to clin­i­cians work­ing in and around the Hawaii Family Court. Well, a new vari­ety of shark has recently been sighted in Hawaii waters. These are main­land foren­sic psy­chol­o­gists who have started com­ing to Hawaii to sell their […]