Wechsler Arithmetic test: Measure of Gq or Gf?

What does the Wechsler Arithmetic test measure? Why has it's interpretation been so variable over the decades? Why is it now classified (as per CHC theory) as a mixed measure of Gsm (Short-term Memory - Working memory; MW) and Gf (Fluid Reasoning - Quantitative reasoning; RQ) in the latest Essentials of Cross-Battery Assessment book (Flanagan, Ortiz and Alfonso, 2007)? [Click here if you need more information on CHC theory and the major abilities, definitions, and abbreviations]

While preparing for my recent presentation at the Third National School Psychology Neuropsychology Conference, I consulted the 2nd edition of the Essentials of Cross-Battery book. I noticed on page 310 that, in contrast to prior cross-battery classifications of the Arithmetic test as a primary measure of Gq (Quantitative Knowledge-Math Achievement; A3) and Gf (Fluid Reasoning-Quantitative Reasoning; RQ) [Note - I was involved in these prior classifications as a coauthor of the first cross-battery book (ITDR: McGrew and Flanagan, 1998) and the Wechsler-specific spin-off cross-battery book (Flanagan, McGrew & Ortiz, 2000), it had now changed to Gsm and Gf.

First, a historical note. In the ITDR and Wechsler cross-battery books the primary Gq classification was based on a series of CHC/Gf-Gc designed cross-battery (joint) factor studies. The secondary Gf classification was a logical content analysis based classification, for which no available CHC/Gf-Gc cross-battery factor analysis supported the classification.

A review of page 310 in the 2nd Edition of the Essentials of CB indicates that the Gsm and Gf classifications are based on "factor analysis from the WISC-IV technical and interpretive manual (Psychological Corporation, 2003) and from the results of factor analysis reprted in Keith, Fine, Taub, Reynolds, and Kranzler (2006)." My problem with this change is that these supporting analyses are all within-battery (WISC-IV only) confirmatory factor analysis studies (CFA), and thus do not include the complete range of CHC indicators in the analysis, especially other Gq markers. If you want to see a prior post I made about my disagreement with the Keith et al. Arithmetic classification, click here. Personal communication with one of the XBA Essentials books authors indicates that the Gf classification is also intended to reflect content validity evidence.

Why do I take issue with the use of within-battery CFA to make CHC test classifications? If you want the long story you can read about the strengths and limitations of within- and cross-battery CFA studies in the first two XBA books listed above. If you want a short-course on the issue, you can check out an on-line PPT show I just uploaded that conceptually illustrates the limitations of within-battery CFA studies....and...more importantly, the advantage of CHC-designed cross-battery (joint) CFA studies classifying tests as per CHC theory.

To date I know of 9 different Wechsler/Woodcock-Johnson CHC/Gf-Gc designed cross-battery studies. All 9 studies include other markers of Gq (math achievement tests). In ALL of these analysis the Wechsler Arithmetic test has a large a significant loading on Gq (average loading in the mid .70's)....none on Gf. In one study (Phelps et al. 2005) there is a small secondary loading on Gs. In none of these cross-battery studies does Arithmetic display a significant Gsm factor loading. You can view a summary of these CHC-designed cross-battery findings, as well as the Keith et al. (2006) model upon which the current (and I believe inaccurate) Arithmetic Gf classification is based (due to a loading of .79 on a Gf factor), at the following link.

My two cents. I believe the best available analysis argue for the Wechsler Arithmetic test being interpreted primarily as a measure of Gq (Math Achievment-A3). I believe practitioners should not interpret this test as a primary or strong measure of Gf (Fluid Reasoning - Quantitative Reasoning; RQ). This does not mean that RQ is probably not involved. What the data indicate that if RQ is involved, the amount of variance is trivial and dwarfed by Gq-A3.

Conflict of interest disclosure - I'm a coauthor of the WJ III and thus have a financial interest in a competitor to the Wechsler batteries. I no longer receive any royalties from the two respective cross-battery books I coauthored.

IQs Corner APA book nook 7-18-08

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A new issue of PsycCRITIQUES is available online. If you would like subscription information, please go to http://www.apa.org/psyccritiques. If you have a subscription to the product and experience any access problems, please go to http://members1.apa.org/memhelp1.html. July 16, 2008 Volume 53, Issue 29 Book Reviews 1. Sex Offending: Causal Theories to Inform Research, Prevention, and Treatment Authors: Jill D. Stinson, Bruce D. Sales, and Judith V. Becker Reviewer: Stephen P. Hampe 2. Cognitive-Behavioral Therapy for Smoking Cessation: A Practical Guidebook to the Most Effective Treatments Authors: Kenneth A. Perkins, Cynthia A. Conklin, and Michele D. Levine Reviewers: Maria Karekla, Marios Constantinou, and Yianna-Maria Stylianou 3. Taken Into Custody: The War Against Fathers, Marriage, and the Family Author: Stephen Baskerville Reviewer: Gordon E. Finley 4. The Shock Doctrine: The Rise of Disaster Capitalism Author: Naomi Klein Reviewer: Tod Sloan 5. Healing Tales: The Narrative Arts in Spiritual Traditions Authors: Stanley Krippner, Michael Bova, Leslie Gray, and Adam Kay (Eds.) Reviewer: Louise Sundararajan Healing Stories: The Use of Narrative in Counseling and Psychotherapy Authors: Stanley Krippner, Michael Bova, and Leslie Gray (Eds.) Reviewer: Louise Sundararajan 6. Physical Illness and Schizophrenia: A Review of the Evidence Authors: Stefan Leucht, Tonja Burkard, John H. Henderson, Mario Maj, and Norman Sartorius Reviewer: John W. Newcomer 7. Cognitive Diagnostic Assessment for Education: Theory and Applications Authors: Jacqueline P. Leighton and Mark J. Gierl (Eds.) Reviewer: Howard T. Everson 8. Lesbian Motherhood: Stories of Becoming Author: Amy Hequembourg Reviewer: Susan Lonborg 9. Creativity, Mental Illness, and Crime Author: Russell Eisenman Reviewer: Marlene M. Eisenberg 10. Why Do They Kill? Men Who Murder Their Intimate Partners Author: David Adams Reviewer: Henck van Bilsen 11. Assessment of Feigned Cognitive Impairment: A Neuropsychological Perspective Author: Kyle Brauer Boone (Ed.) Reviewers: James Robert Youngjohn and Michael Lee Thomas Film Review 12. The Brave One Director: Neil Jordan Reviewer: Jerry Gold

Dr. Richard Woodcock Neuropsych Keynote slide show: Evolution of Cognitive Assessments

A copy of Dr. Richard Woodcock's Keynote address (The Evolution of Cognitive Assessments) at the Third National School Psychology Neuropsychology conference (Dallas, July 10, 2008) is now available for viewing as an on-line PPT show (that can also be downloaded). Click here to go to my SlideShare site where this is now available. The slides do not contain everything Dr. Woodcock presented as certain copy-protected information was removed prior to posting. Also, his personal comments/stories about the serendipitous events that brought him to the field of psychoeducational test development are not included in the slides.

Excercise may limit brain shrinking

Another benefit to excercise as we age.

http://www.cnn.com/2008/HEALTH/conditions/07/14/alzheimers.exercises.ap/index.html?eref=rss_topstories

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CHC narrow abilities related to reading and math slide posted

I just returned from the National School Psychology Neuropsychology conference in Texas. A great conference with a very competent crowd of people to present to.

During my presentation it was brought to my attention that one of my key PPT slides/handouts (Key CHC narrow abilities important for reading and math achievement) on the all-presenter handout/slide CD was difficult to view due to problems with the shading scheme I had used. I promised to make a clean copy available via my blog for the participants. I've now posted three different versions of this slide for download. The formats provided are: PPT slide; JPEG image; PDF file. Take your choice and select whatever looks best for you.

Thanks for your patience. I hope to attend and present at this conference in the future.

Computerized cognitive testing

MOBILE PHONE POST.

Sharp Brains has a good post summarizing the recent activity in large
scale computerized cognitive testing. See link below.

http://www.sharpbrains.com/blog/2008/07/14/computerized-cognitive-assessments-opportunities-and-concerns/

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Smart girls and boys use different parts of brains?

MOBILE PHONE POST

From ENL a study suggesting what prior research has suggested in the
past-boys and girls tax different parts of their brains when
performing certain activities.

http://eideneurolearningblog.blogspot.com/2008/07/smart-girls-smart-boys.html

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