Monday, September 7, 2009

Use of the Mexican WAIS-III in MR capital Atkin cases: Controversy reported in Applied Neuropsychology journal

Is the Mexican normed version of the WAIS-III appropriate for use in diagnosing mental retardation and, more importantly, is it appropriate for use in Atkins MR death penalty cases? Apparently a controversy has surfaced re: this question as reflected by three articles in the journal Applied Neuropsychology.

As background note, I've blogged previously about a special issue of this journal that dealt with Atkins cases. I've not completed reading all of those articles yet...there simply is not enough time in my day.

Given my obvious conflict of interest [I'm a coauthor of the competing WJ III and BAT III], I will not render any judgment "pro" or "con" regarding the debate. Instead, I'm making available (below) the abstract of a series of three articles published in the latest issue of Applied Neuropsychology that address the issue. Suen and Greenspan (2009a) make the case against the use of the Mexican WAIS-III. Escobedo and Hollingworth (2009) respond to Suen and Greenspan (2009a). Suen and Greenspan (2009b) then respond to Escobedo and Hollingworth (2009).

Readers will need to review the articles and make their own informed judgments. I would like to invite appropriatelly qualified scholars to consider submitting a guest comment post on all three articles and any other journal published research that bears on this specific controversy. If interested, contact me at my email in my "About Me" section of this blog. In addition, given my conflict of interest, I am requesting that anyone familiar with any similar controversies or questions regarding the BAT III to bring them to my attention as I would make those published articles available for review...also without comment.

Suen, H. K. & Greenspan, S. (2009a). Serious Problems with the Mexican Norms for the WAIS-III when Assessing Mental Retardation in Capital Cases. Applied Neuropsychology, 16 (3), 214-222. (click here).
A Spanish-language translation of the Wechsler Adult Intelligence Scale-III (WAIS-III), normed in Mexico, is sometimes used when evaluating Spanish-speaking defendants in capital cases in order to diagnose possible mental retardation (MR). Although the manual for the Mexican test suggests use of the U.S. norms when diagnosing MR, the Mexican norms—which produce full-scale scores on average 12 points higher— are sometimes used for reasons that are similar to those used by proponents for ‘‘race-norming’’ in special education. Such an argument assumes, however, that the Mexican WAIS-III norms are valid. In this paper, we examined the validity of the Mexican WAIS-III norms and found six very serious problems with those norms: (1) extremely poor reliability, (2) lack of a meaningful reference population, (3) lack of score normalization, (4) exclusion of certain groups from the standardization sample,(5) use of incorrect statistics and calculations, and (6) incorrect application of the true score confidence interval method. An additional problem is the apparent absence of any social policy consensus within Mexico as to the definition and boundary parameters of MR. Taken together, these concerns lead one to the inescapable conclusion that the Mexican WAIS-III norms are not interpretable and should not be used for any high-stakes purpose, especially one as serious as whether a defendant should qualify for exemption against imposition of the death penalty.

Escobedo, P. S. & Hollingworth, L. (2009) Annotations on the Use of the Mexican Norms for the WAIS-III. Applied Neuropsychology, 16 (3), 223-227 (click here).
This article provides crucial information to judge the appropriateness of the Mexican version of the Wechsler Adult Intelligence Scale-Third Edition and recognizes some limitations in both the process of its adaptation to the Mexican population and the norm development process. This is an effort to contribute to the debate initiated by Suen and Greenspan (2008), who argued in court against the use of Mexican norms in a death penalty case, which depended upon establishing the diagnosis of mental retardation. As a part of the defense team, these scholars argued a number of points against the use of the Mexican norms. With input from the lead researcher on the Mexican standardization process, some of the criticisms are addressed, and further information about the norm development process for this test in Mexico is provided in an attempt to be critical about the strengths and weaknesses of the use of existing Mexican norms. Finally, we argue that results from a single test must not be used to make life and death decisions and that test development is a continuous process influenced by culture,language, and indeed by norm-developing procedures and debates.

Suen, H. K. & Greenspan, S. (2009). Reply to Sanchez-Escobedo and Hollingworth: Why the Mexican Norms for the WAIS-III Continue to be Inadequate. Applied Neuropsychology, 16 (3), 228-229 (click here).
The discussion in Drs. Sanchez-Escobedo and Hollingworth’s paper independently confirms virtually all our observations regarding the psychometric and interpretive deficiencies of the Mexican norms for very high-stakes decisions, such as that involved in an Atkins hearing. Test publishers have an ethical obligation to caution potential users against the premature use of a developing assessment that does not yet meet the needed precision and evidence of validity required for very high-stakes decisions.

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