By Interactive Metronome - January 13, 2012
Dr. McGrew conducts research in the areas of theories of human intelligence, intelligence testing, school learning, and the application of neurotechnology to cognitive performance and learning. He has published over 60 different journal articles, books or book chapters in his areas of expertise. He is a coauthor of theWoodcock-Johnson Battery III. Detailed information can be found at his the IAP web page. McGrew disseminates information regarding human intelligence and the human brain clock at two professional blogs (IQs Corner; Brain Clock Blog).
Why did you get into the IQ testing business?
As a school psychologist during the early years of federal special education laws, I was giving hundreds of IQ tests to school children ach year. I enjoyed the art and science of a good assessment. Then, serendipity struck and I heard of Alan Kaufman’s 1979 book, Intelligent Testing with the WISC-R, the primary test used at the time. I strongly resonated to Kaufman’s art+science approach to “intelligent” IQ testing. Then, serendipity struck again when a complimentary copy of the upstart 1977Woodcock-Johnson Psychoeducational Battery (WJ) showed up on my desk. I saw the tremendous potential of the WJ and convinced our special education system to switch to it exclusively, and concurrently set of up database to capture all test scores generated in the school system. I started teaching myself psychometeric methods that would allow me to interpret the WJ as per the Kaufman “intelligent” testing philosophy. I eventually started publishing articles (while still being a practicing school psychologist) which led to another serendipitous event—a chance meeting with Dr. Woodcock at an LD conference in MN. I shared what I was doing, we started communicating, and within a few years I was doing part-time data analysis for Dr. Woodcock on a number of his tests. This led to the opportunity for me to travel so I could work and live with him for a week to complete a special project. This week started my apprenticeship as an applied intelligence test developer and psychometrician—an apprenticeship with probably the most gifted developer of applied cognitive and achievement tests during the past four decades. I then decided I needed to write my first book, Clinical Interpretation of the Woodcock-Johnson Tests of Cognitive Ability, which was my attempt to teach school psychologists how to use Kaufman’s intelligent testing philosophy with the WJ cognitive battery.
Which IQ tests have you created and how are they different from all the others?
My first experience was not in creating the tests, but was in serving as the primary measurement consultant during the revision and restandardization of the Woodcock-Johnson—Revised (1998). While working concurrently on my doctoral degree, I completed the primary statistical analysis, calculated all the norms, and was first author on the WJ-R technical manual. I was not a coauthor of the test. Post publication I wrote extensively, made many professional presentations, and revised my first book to help with interpretation of the WJ-R cognitive battery. Then, when the third edition was being planned, I was asked by Dr. Woodcock to join him, along with Dr. Nancy Mather, as new co-authors of the Woodcock-Johnson—Third Edition (WJ III). In this role I was involved in more aspects of test development, including developing prototype new subtests and items, training people to gather the norm data, and again completing all the psychometric and statistical analysis. The WJ III gave me a chance to learn about the complete and detailed process of applied test development—a process few people realize as being so time consuming, expensive, and lengthy. It is not all glamorous work.
The WJ III differs in multiple ways from other IQ test batteries, with the most obvious difference being the battery was the first to be designed to operationalize the consensus psychometric theory of intelligence—the Cattell-Horn-Carroll (CHC) of cognitive abilities. Most all other individual IQ tests now are modeled on the CHC model, either explicitly or implicitly. The WJ III is the most comprehensive IQ test available and is unique in its measurement of a wider array of abilities that most other tests (e.g., long-term storage and retrieval tests; tests of auditory processing-abilities not often measured by other individual IQ tests).
What’s the point of IQ tests?
A proper answer to this question would require a chapter since IQ tests serve multiple functions in different contexts and settings. A primary purpose is to establish a person’s current level of general level of intellectual functioning to assist with eligibility and classification for services (e.g., special education; social security benefits). But their real value comes from going beyond the total single IQ composite score. In the hands of a skilled “intelligent” clinician, the best use of IQ batteries is to help others (e.g., teachers; parents), or the person themselves, understand a person’s unique pattern of cognitive strengths and weaknesses. There is only one proven law of psychology—the law of individual differences. A comprehensive and valid IQ test in the hands of an astute clinician is a valuable tool for elucidating the the individual differences in cognitive abilities of each person, with the goal to design better environments (educational, employment) to better “fit” the person’s unique pattern of learning.
What are some of the biggest misuses you’ve seen of IQ tests?
IQ tests have a bad reputation in many crowds. This is unfortunate as they are the most scientifically sound and empirically researched tools that have emerged from the field of psychology. I am fond of saying that “if you give a monkey a Stradivarius violin and you get bad music, you don’t blame the violin!” The biggest problem is when people (lay people, the media and psychologists themselves) believe too much in the power of IQ tests. The result can be statements or predictions that imply the tests can drill a shaft into a person’s head, locate the magical IQ for that person, and then make precise statements and predictions. IQ tests are fallible measures of a persons general intelligence of intellectual functioning at a specific point in time. There are many specific misuses I could mention, but they all tend to fall under this one category—misuse by someone who does not recognize both the strengths and limitations of the tools. IQ tests are dumb tools—they are only as good as the clinician who is using them, much like medical tools are dumb tools and are only good if interpreted by a skilled doctor.
How are you trying to go beyond IQ?
If you took the WAIS-R IQ test score I received while being a test subject as an undergraduate psychology major, as well as my Miller’s Analogies or GRE scores that were part of my application for a doctoral program, you would not expect me to be as successful as I have been. Predictions would have suggested lower expectations. In fact, I was initially turned down at two psychology doctoral programs. I believe my GRE and Miller’s test scores played a role. The third time was the charm, but only after I had produced clear products (e.g., journal articles; a book) that demonstrated I had some kind of abilities. Whenever I become passionate about a topic, I throw myself at the topic with extreme perseverance, long hours of reading, and constant self-study. I have seen the same for many students with low tested cognitive abilities—the bigotry of soft expectations. Yet, some of these students amaze and exceed what their IQ score may suggest. Psychology calls these conative or non-cognitive variables which include such constructs as motivation, self-efficacy, self-regulated learning strategies, goal orientation, to name a few. Others use other terms like grit or determination.
IQ tests, at their best, can only explain 40-50 % of school achievement and has proven hard to increase via cognitive interventions. Aside from important external environmental variables (e.g., quality of instruction; home environment), I believe that a significant portion of the remaining 50-60% of achievement is related to these non-cogntive variables, which I have articulated in a framework called the Model of Academic Motivation and Competence (MACM). Although these traits may not correlate as high as the powerful IQ score with various outcomes, the non-cognitive abilities are more manipulable and subject to intervention. They are levers we can utilize to benefit individuals. I believe education has ignored these important non-cognitive variables, particularly since the No Child Left Behind (NCLB) initiative began during the Bush presidency. I believe that the old concept of aptitude should be re-introduced, which is the notion that a person has a propensity to achieve in certain domains due to the combination of their unique set of cognitive and conative abilities. Cognitive+conative=aptitude for a specific domain. We need to supplement IQ tests with measures of these other critical and more malleable traits of individuals.
What do you think the future of IQ testing looks like?
I hate making predictions but will offer a few. We have reached the ultimate threshold on the predictive power of IQ tests and will not see advances in correlations with various outcomes. I believe more tests will be designed as per the CHC theory of intelligence. I see a decreasing emphasis on the global IQ score and an increased focus on interpretation of more narrow specific ability scores (based on combinations of 2-4 tests from a battery). I see more selective testing, where the IQ battery is viewed as more of a tool box and good clinicians choose those tools (set of subtests) to address the unique questions asked regarding a person—a de-emphasis on the single global IQ score. I also see more web- and tablet/iPad based delivery of IQ tests. Finally, I see test developers or after-market experts harnessing the power of computers to develop “expert systems” for interpretation of IQ tests.
Where can people go to find out more about your important work?
The two primary sources are my consulting corporation’s web page (Institute for Applied Psychometrics, IAP—www.iapsych.com) and my IQ’s Corner blog (www.iqscorner.com). I also have an intense interest in emerging brain fitness neurotechnologies, particularly those that seem to be impacting the brains internal clock(s). My Brain Clock blog (