Monday, October 5, 2009

Race Rears Its Ugly Head in Atkins case: Guest post by Kevin Foley

Race and IQ tests has been one of the most hotly debated controversies in the field of intelligence testing (click here for some recent post over at sister blog--IQs Corner).  To most psychometrician/measurement experts, the mere presence of mean IQ score differences does not meet the psychometric definition of test bias.  We measurement types typically define test bais as: (a) item content bias, which is now commonly removed via expert panels and differential item functioning [DIF] item analysis methods, (b) structural bias, which means that a test doesn't measure the same constructs across groups [and which is typically evaluated with confirmatory factor analysis structural invariance methods], and (c) predictive bias, which means that a test differentially predicts outcomes for different groups [and which is typically evaluated via the examination of potential differential prediction regression slopes].  Most contemporary intelligence tests address all forms of psychometric bias during test development.

The above mini-course not withstanding, Kevin Foley has written another excellent and though-provoking guest  post (click here to see his prior guest post) dealing with the introduction of racial bias claims, with an unusual "spin" on the interpretation of bias, in the context of experts testifying in an Atkins MR death penalty case in Tennessee.  K. Foley's guest post is reproduced "as is" with any URL links added by the blogmaster.  Thanks Kevin Foley for another well written and provocative post.

In an Atkins case out of Tennessee, two prosecution experts “testified that I.Q. tests have historically been biased against minorities in that they tend to underestimate the intelligence of minorities.” Memorandum Decision, Black v. Bell, ( U.S. Dist. Ct., M.D.Tenn., No. 3:00-0764, Apr. 24, 2008). In an Ohio Atkins case involving convicted murderer Kevin Yarbrough, the State “contend[ed] that the early tests were given at a time that IQ tests were culturally biased against minorities and could have lowered the test results”. Decision Order/Entry, State v. Yarbrough, Ohio Common Pleas Court, Shelby County, Case No. 96CR000023 (Feb. 28, 2007). In a similar vein, the trial court in Ex Parte Chester (unpub., Tex. Ct. Crim. App., No. AP-75,037 (2007)) refused to accord appropriate weight to childhood IQ scores obtained by Chester because the WAIS-R “would not adequately account for cultural, regional, or other types of factors that may have influenced [Chester’s] test results.” Since Chester is black, and his native “region” is reported to be Jefferson County, Texas, the import of this comment obviously refers to his racial background. Two other examples include the case of Eldridge v. Quarterman, 2008 U.S. Dist. LEXIS 19647 (S.D. Tex. 2008), where there was testimony from a psychologist who “acknowledged evidence that minorities score artificially low”, and Maldonado v. Thaler, 2009 U.S. Dist. LEXIS 88988 (S.D. Tex.) (prosecution expert testified that “cultural differences” probably artificially lowered immigrant defendant’s scores).

The author of a recent law review article about the consequences of Atkins asserted that, “There is evidence that some IQ tests feature an inherent cultural bias that leads some minority groups to score lower than other individuals.” M. Libell, Atkins’ Wake: How the States Have Shunned Responsibility for the Mentally Retarded, 31 Law & Psychol. Rev. 155, 162 (2007). Similarly, the author of another law review article claimed that, as a consequence of “flawed” IQ tests, “[e]conomically deprived people and ethnic minorities are . . . often erroneously found to be mentally retarded.” Lori M. Church, Mandating Dignity: The United States Supreme Court's Extreme Departure From Precedent Regarding the Eighth Amendment and the Death Penalty, 42 Washburn L.J. 305, 325 (2003).

Starting with Arthur Jensen’s tome, Bias in Mental Testing (1987), there is long list of scientific literature which would seem to indicate that IQ tests are not biased against minorities. Even though there is gap of approximately one standard deviation between the mean IQ scores of blacks and whites, and about half that amount between whites and Hispanics, that does not mean that IQ tests are biased.

Are the psychologists referred to above showing a bias of their own in attempting to give their party the testimony they want, and are the prosecutors, courts and legal commentators simply providing spin based on myth, not science? It would be nice to hear from some objective psychologists on this issue. Should comments like those above by made by experts in Atkins cases and in the discussions of commentators?
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