Tuesday, July 29, 2014

Quotes to note: Importance of high quality psychological testing to psychologists

I just read this nice statement at the begging of the following article by Robert J. Ivnik, Ph.D., ABPP Professor of Psychology, Mayo Clinic College of Medicine, Rochester, MN.

The only professional services that are uniquely psychology's are testing-based assessments. Every other service that psychology offers can be obtained from other professions. In light of testing's central importance to our profession, and considering the number of years that psychologists have been practicing, we assure that our tests are scientifically sound and have been validated for the purposes to which they are put (e.g., research proves that our tests make accurate predictions). Correct? After all, in today's health care environment would any profession knowingly expose its core service to potential attack?

Although testing-based assessments are psychology's defining feature, they may also be our profession's Achilles' heel. Unfortunately, the manner in which many tests have been developed, standardized, normed, and validated may be most kindly described as ‘‘varied'' when it comes to scientific rigor. The science behind some of psychology's older and commercially successful tests tends to be stronger when some of the profit accrued by their sale is devoted to improving the tests. Lacking similar financial resources, many other tests have simply not been developed or validated very well

Click on image to enlarge.

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Fwd: [ABA-3D] Webinar Announcement

Suspects/Offenders' Issues Series:

Alternatives to Incarceration for Criminal Offenders with Developmental and Intellectual Disabilities


August 28, 1:30-2:30 p.m. EST

Jessica S. Oppenheim, Esq.

Director of the Criminal Justice Advocacy Program of The Arc of New Jersey

Criminal Offenders with developmental and intellectual disabilities (I/DD) present unique challenges to the criminal justice system seeking to investigate and prosecute crime as well as to the social service system seeking to serve and assist this vulnerable population. Such individuals make up at least 9 – 10% of the prison population and some studies tell us that they may comprise as much as 50% of adult and juvenile offender populations. It is unquestioned that individuals with I/DD face distinct disadvantages in the system, resulting in convictions for more serious offenses and more prison time.


The Criminal Justice Advocacy Program (CJAP) of The Arc of NJ seeks to overcome these disadvantages, while still ensuring that offenders take responsibility for criminal behavior, by arranging specific interventions that provide alternatives to incarceration through offender-specific Personalized Justice Plans. The CJAP also acts as a clearinghouse of information between the criminal justice and social service system in provide training and communication between the two systems. This webinar will review the obstacles and disadvantages faced by this population and provide an overview of the CJAP.  Register here

The Arc's National Center on Criminal

Justice & Disability (NCCJD)

Webinar Series

MISSIONNCCJD will become the national focal point for the collection and dissemination of resources and serve as a bridge between justice and I/DD professionals. NCCJD will pursue and promote safety, fairness and justice for all people with intellectual and developmental disabilities as suspects, offenders, victims or witnesses. For more information: http://www.thearc.org/NCCJD

Contact: Kathryn Walker, Criminal Justice Fellow    Phone: 202.534.3700    Email: NCCJDInfo@thearc.org






    Kathryn J. Walker, J.D., M.P.H.

Criminal Justice Fellow

The Arc 

1825 K Street NW, Suite 1200, Washington, D.C. 20036

Phone:  202.600.3491 | Toll free: 800.433.5255

Fax: 202.534.3731

Email: kwalker@thearc.org


Follow us online at:   




You can help build The Arc by making a secure, online contribution by visiting www.thearc.org/donate. Thank you for supporting the work of The Arc.


Saturday, July 26, 2014

More on Greenspan's model of personal competence: Relationship between IQ and social, practical, and conceptual abilities

I am pleased to see that, after a relatively long draught in published research, someone is again investigating the relations between general intelligence, and the primary domains of adaptive behavior, in models (that when examined closely) that are investigating aspects of Greenspan's' model of personal competence. The title, abstract, and key figure from this new research follow. The article can be read here. Kudos to these researchers

Click on images to enlarge

My primary criticism of this study is that it completely ignores the primary foundation research in this area that occurred between 1990 and 2000, some of which are the primary research studies cited in the AAIDD manuals to support the domains of practical, conceptual and social competence (Greenspan's model). I have provided a list of that research, and results from the most prominent article from that group of researchers, below.

Yes, my name is all over these MIA studies (in the current featured article) so some could see my comments as academic sour grapes for being overlooked. But I see their omission as a lack of scholarly rigor by the researchers and the journal who published the current article. All of the MIA studies can be found at the MindHub--scroll down until you see the list of studies shown above. Then click away and download and read. It would have been nice if the new study results would have been integrated with the extant personal competence research literature.

In the final analysis I am pleased that someone is conducting much needed research on these constructs given the pivotal role they play in the definition and assessment of MR/ID.

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Friday, July 25, 2014

The new WJ IV: Introductory webinar and author video interviews

The publisher of the new WJ IV Battery just posted an on-line video of Dr. Fred Schrank's WJ IV introduction and overview webinar and brief video interviews of the three WJ IV authors. They can be found here.

[Conflict of interest disclosure: I am one of the coauthors of the WJ IV].

I am much younger looking than my video interview suggests :)

- Posted using BlogPress from my iPad

Tuesday, July 15, 2014

The Flynn Effect Archive Project: 7-15-14 update

I am pleased to announce an update of the Flynn Effect Archive Project. Information on the project and how to access the on-line archive can be found at this link.

Click on image to enlarge.

- Posted using BlogPress from my iPad

Monday, July 7, 2014

2014 BEST IN category - Proud of my daughter Beth..the artist behind this winning photo


Kevin McGrew, PhD
Educational Psychologist
Director, Institute for Applied Psychometrics

Thursday, July 3, 2014

Law Review Article: Advantages of DSM-5 in the Diagnosis of Intellectual Disability: Reducing Reliance on IQ Ceilings in Atkins (Death Penalty) Cases

Haydt, Greenspan, and Bhushan's (2014) recent law review article on the possible advantages of using DSM-5 in Atkins cases can be found here.

Atkins MR/ID Death Penalty Court Decisions: Brumfield v Cain (Louisiana, 2014)

Sorry for the delay in posting Brumfield v Cain (Louisiana, 2014).

Information regarding prior Brumfield decisions can be found here.

The most comprehensive synthesis of the Flynn effect (effect size) literature to date

Trahan et al. (2014) have just published the most comprehensive meta-analysis of the size of the Flynn effect (norm obsolescence) to date. This is seminal work adds significant credibility to the Flynn effect as a scientific fact. Link to article above. Click on image to enlarge the abstract. I promise that one of these days I will update the Flynn Effect Archive Project. I have many other articles to add.

Friday, June 20, 2014

Sharing The unitary ability of IQ in the WISC-IV and its computation via BrowZine

The unitary ability of IQ in the WISC-IV and its computation
Orsini, Arturo; Pezzuti, Lina; Hulbert, Sabina
Personality and Individual Differences, Vol. 69 – 2014: 173 - 175


University of Minnesota Users:

Non-University of Minnesota Users: (Full text may not be available)

Accessed with BrowZine, supported by University of Minnesota.

Monday, June 9, 2014

Assessing the Flynn Effect in the Wechsler scales. [feedly]

Assessing the Flynn Effect in the Wechsler scales.
// Journal of Individual Differences - Vol 31, Iss 2

The current study examined the Flynn Effect (i.e., the increase in IQ scores over time) across all editions of the Wechsler Adult Intelligence Scale (WAIS), Wechsler Intelligence Scale for Children (WISC), and Wechsler Preschool and Primary Scale of Intelligence (WPPSI). By reverse engineering the correlation and scale score transformations from each Wechsler edition's technical manual, we made a mean and covariance matrix using the subtests and age groups that were in common for all editions of a given instrument. The results indicated that when aggregated, there was a FE of 0.44 IQ points/year. This Wechsler instrument used, however, moderates the FE, with the WISC showing the largest FE (0.73 IQ points/year) and the WAIS showing a smallest FE (0.30 IQ points/year). Moreover, this study found that the amount of invariant indicators across instruments and age groups varied substantially, ranging from 51.53% in the WISC for the 7-year-old group to 10.00% in the WPPSI for the 5- and 5.5-year-old age groups. Last, we discuss future direction for FE research based on these results. (PsycINFO Database Record (c) 2014 APA, all rights reserved)

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Kevin McGrew, PhD
Educational Psychologist
Director, Institute for Applied Psychometrics

Saturday, June 7, 2014

Is biculturalism a three dimensional construct?

Interesting article suggesting that biculturalism (and not degree of acculturation and enculturation) may be a three dimensional construct. Click on images to enlarge.






Wednesday, May 28, 2014

Hall v. Florida Impact: 20 Cases? [feedly]

Hall v. Florida Impact: 20 Cases?
// Crime and Consequences Blog

How many cases will yesterday's decision in Hall v. Florida actually impact?  Lizette Alvarez and John Schwartz have this article in the NYT estimating "10 to 20," citing anti-death-penalty law professor John Blume for that estimate.  (The article doesn't identify Blume as an advocate for one side on this issue, but he is.) "The death row inmates in this category would generally have I.Q.'s of between 71 and 75. Inmates in that category should now be able to ask for a new hearing that would take into consideration other evidence and a broader range of I.Q. tests."

There are a couple of points to note here.  First, it appears a prominent advocate for the other side implicitly agrees that Hall does not require reconsideration in cases where the inmate's test scores are above 75.  My prior post and the comments to it discussed whether Hall might extend to murderers whose scores are consistently above 75.  I don't think it does yet -- and apparently Blume agrees -- though the Court may still go there in the future.

Does everyone in the 71 to 75 twilight zone automatically get a new hearing?  If that means evidentiary hearing, I don't think so.  Hall himself, for example, put on the experts who testified to the same thing they would testify to after the Supreme Court's decision.  I don't see any reason why the trial judge cannot enter a new decision on the same record, considering the margin of error as the Supreme Court directs.  I expect his decision would be the same.  The state might want a new evidentiary hearing to put on the evidence it didn't think was necessary before, but Hall has already had his shot.


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Article: Justice Alito’s Statistics Lesson Misses the Mark in Recent Dissent, Experts Say

Justice Alito's Statistics Lesson Misses the Mark in Recent Dissent, Experts Say

Sent via Flipboard

Blogmaster, Dr. Kevin McGrew, participates in Huffington Post live stream interview this morning: WATCH: Death Row Inmates With Low IQs Get 2nd Chance

Thought you might enjoy this video:


Death Row Inmates With Low IQs Get 2nd Chance

In a 5-4 decision on Tuesday, the US Supreme Court struck down Florida's IQ execution law, which was used to determine mentally disabled inmates' eligibility for execution, calling it "unconstitutional."

Wednesday, May 21, 2014

CHC theory 101: \"Big picture\" context and from Spearman's g to contemporary CHC - new SlideShare modules

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Saturday, April 19, 2014

Why composite scores are more extreme than the average of their parts [feedly]

The brilliance of Dr. Joel Schneider   

Why composite scores are more extreme than the average of their parts
// Assessing Psyche, Engaging Gauss, Seeking Sophia

Suppose that two tests have a correlation of 0.6. On both tests an individual obtained an index score of 130, which is 2 standard deviations above the mean. If both tests are combined, what is the composite score?

Our intuition is that if both tests are 130, the composite score is also 130. Unfortunately, taking the average is incorrect. In this example, the composite score is actually 134. How is it possible that the composite is higher than both of the scores?

If I measure the length of a board twice or if I take the temperature of a sick child twice, the average of the results is probably the best estimate of the quantity I am measuring. Why can't I do this with standard scores?

Standard scores do not behave like many of our most familiar units of measurement. Degrees Celsius have meaning in reference to a standard, the temperature at which water freezes at sea level. In contrast, standard scores do not have meaning compared to some absolute standard. Instead, the meaning of a standard score derives from its position in the population distribution. One way to describe the position of a score is its distance from the population mean. The size of this distance is then compared to the standard deviation, which is how far scores typically are from the population mean (more precisely, the standard deviation is the square root of the average squared distance from the mean). Thus, the "standard" to which standard scores are compared are the mean and standard deviation.

An index score of 130 is 2 standard deviations above the mean of 100.

An index score of 130 is 2 standard deviations above the mean of 100.

The average of two imperfectly correlated index scores is not an index score. Its standard deviation is smaller than 15 and thus our sense of what index scores mean does not apply to the average to two index scores. To make sense of the composite score, we must convert it into an index score that has a standard deviation of 15.

\dfrac{(130+130-2*100)}{\sqrt{2+2*0.6}}+100\approx 134

How is this possible. It is unusual for someone to score 130. It is even more unusual for someone to score 130 on two tests that are imperfectly correlated. The less correlated the tests, the more unusual it is to score high on both tests.

Below is a geometric representation of this phenomenon. Correlated tests can be graphed with oblique axes (as is done in factor analyses with oblique rotations). The cosine of the correlation is the angle between the axes. As seen below, the lower the correlation, the more extreme the composite. As the correlation approaches 1, the composite approaches the average of the scores.

The lower the correlation, the more extreme the composite score.

The lower the correlation, the more extreme the composite score.


In a previous post, I presented this material in greater detail.


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Thursday, April 3, 2014

Sharing A Flynn effect among deaf boys in Saudi Arabia via BrowZine

A Flynn effect among deaf boys in Saudi Arabia
Bakhiet, Salah eldin Farah Attallah; Barakat, Serry Mohammed Roshdy; Lynn, Richard
Intelligence, Vol. 44 – 2014: 75 - 77


Tuesday, April 1, 2014

\"Revisiting intellectual disability and the death penalty\" in APA Monitor - April 2014

I found "Revisiting intellectual disability and the death penalty" in Monitor - April 2014
April 2014

Monitor - April 2014

I thought you would enjoy "Revisiting intellectual disability and the death penalty" from Monitor - April 2014

Click the thumbnail or here to go to the issue.

If you cannot click on the links, paste this link into a browser:

Wednesday, March 5, 2014

Article: New evidence confirms link between IQ and brain cortex

This study was previously posted, with comments, at my ICDP blog, where a link is provided to an annotated copy of the article.

Kevin McGrew, PhD
Educational Psychologist
Director, Institute for Applied Psychometrics