Quote2note: Niels Bohr on experts and mistakes

An expert is a man who has made all the mistakes, which can be made, in a very narrow field.

Niels Bohr, recalled on his death, November 18, 1962

#quote2note: #Galton on #measurement

Whenever you can, count.     

              — Sir Francis Galton

#quote2note: Louis Agassiz on stages of #scientific truth

 

"Every great scientific truth goes through three stages. First, people say it conflicts with the Bible. Next they say it had been discovered before. Lastly they say they always believed it."

- Louis Agassiz

#quote2note: Voltaire on #individualdifferences

 

"Minds differ still more than faces"
-Voltaire

#quote2note: All models [#statistical; #scientific] are wrong, but some are useful” (George Box)

 

One of my favorite quotes in the context of statistical models of intelligence or cognitive abilities.

Remembering the "individual" in individual differences research: A quote to note

I just ran across this statement in a recent article (see below). It served as a reminder of something I have always preached, but from-time-to-time, tend to forget as I analyze cognitive ability test data, post research articles, or suggest hypotheses regarding test score differences---be it here at this blog, in a journal article, book, book chapter, or professional presentation. The point being that we must remain vigilant in remembering the "individual" in individual differences research.

The privileged unit of analysis in psychology is the individual (Nesselroade, Gerstorf, Hardy, & Ram, 2007). Nevertheless, many data-analytic approaches coarsely aggregate data and tacitly assume group-average models to hold and to be interpreted in lieu of more fine-grained and, ultimately, person-specific models. For example, when a group of persons show an average increase of performance in a learning task, this does not mean that all persons follow a pattern of change similar to this average. In fact, none of the persons may be well represented by the average trend. In a similar vein, Tucker (1966) argued that the consideration of differences instead of averages will allow us to gain more information about the nature of basic functions underlying behavior. Ever since, researchers have been questioning coarse aggregation of data across persons (e.g., Lamiell, 1981; Nesselroade & Molenaar, 1999) as the estimates of averaged effects may not be representative of any single individual. In fact, strong inference about intra-individual variation from interindividual variation is only possible under the ergodic assumption (Molenaar, 2004), which assumes that the group model represents each individual's dynamics (homogeneity) and that those dynamics have constant characteristics in time (stationarity). In the same vein, Simpson (1951) pointed out that a statistical relationship observed in a population could be reversed within subgroups that form the population. For instance, “It may be universally true that drinking coffee increases one's level of neuroticism; then it may still be the case that people who drink more coffee are less neurotic” (Borsboom, Kievit, Cervone, & Hood, 2009, p. 72). Simpson's paradox may arise whenever inferences are drawn across different explanatory levels, for example, from populations to the individual, or from cross-sectional data to intraindividual change over time (see Kievit, Frankenhuis, Waldorp, & Borsboom, 2013, for further illustrations). Hence, there still is a need for focusing on individuals or subgroups of individuals to more accurately model individual process idiosyncrasies and similarities across persons. Particularly, in light of large-scale empirical data sets, aggregation is more likely to lead to models with low informative value about individual underlying processes as it is often difficult to expand prior hypotheses to account for the large number of potential explanatory variables.

Quote is from this article (click on image to enlarge)



- Posted using BlogPress from my iPad

Quotes to note: The wandering tribes in assessment - Dr. Joel Schneider

Well stated by Dr. Joel Schneider

"The principles of assessment are like a set of unruly and loosely affiliated wandering tribes. There is no established hierarchy of rules, no “Prince of Principles,” and no royal family. There is no Senate, no Supreme Court, no United Nations. Yet, some members are esteemed by all. Others play partisan politics. Some are pompous windbags, others meek speakers of truth. Some are brilliant but impractical, others practical but limited. Some go unnoticed because they are subtle, others because they are so obvious. Some are widely misunderstood and some have outlived their usefulness. Some appear to be senselessly confining but actually protect us from our own excesses and foibles"

In:





- Posted using BlogPress from my iPad

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.


- Posted using BlogPress from my iPad

CHC intelligence theory and testing: Quotes to note from intelligence giants

Regular readers of this blog know that I  frequently reference the need for the Cattell-Horn-Carroll (CHC) theory of cognitive abilities to be used as the organizational framework for intelligence testing.  I typically provide links to two sources (one a pre-pub version of a book chapter that was eventually published; the other an invited 2009 editorial in the journal Intelligence). 

If readers take time to read these sources, they will learn that CHC theory is the combination of Cattell-Horn Gf-Gc theory and Carroll's three-stratum Gf-Gc theory [Carroll, J. B. (1993). Human cognitive abilities:  A survey of factor analytic studies. New York: Cambridge University Press].  I cannot stress enough the importance of the development of CHC theory for evidence-based intelligence theories and test development and interpretation.

To add external credibility to my professional opinion, I suggest skeptical readers read the words of major intelligence scholars as they rendered judgment on the Carroll portion of the CHC model.  Below are a few select quotes.  The conclusion should be obvious. Top notch intelligence scholars recognize the seminal work of Carroll, which is a major cornerstone of CHC theory.  I'll let the words of these giants speak for themselves.

Richard Snow (1993; back cover jacket of Carroll's, 1993 book):

 “John Carroll has done a magnificent thing. He has reviewed and reanalyzed the world’s literature on individual differences in cognitive abilities…no one else could have done it… it defines the taxonomy of cognitive differential psychology for many years to come.”

Burns, R. B. (1994). Surveying the cognitive terrain. Educational Researcher, 35-37.

Carroll’s book “is simply the finest work of research and scholarship I have read and is destined to be the classic study and reference work on human abilities for decades to come” (p. 35).

Horn, J. (1998). A basis for research on age differences in cognitive abilities. In J.J. McArdle, & R.W. Woodcock (Eds.), Human Cognitive Abilities in Theory and Practice (pp. 57-92). Mahwah, NJ: Lawrence Erlbaum.

A “tour de force summary and integration” that is the “definitive foundation for current theory” (p. 58).  Horn compared Carroll’s summary to “Mendelyev’s first presentation of a periodic table of elements in chemistry” (p. 58). 

Jensen, A. R. (2004). Obituary - John Bissell Carroll. Intelligence, 32(1), 1-5.

“…on my first reading this tome, in 1993, I was reminded of the conductor Hans von Bülow’s exclamation on first reading the full orchestral score of Wagner’s Die Meistersinger, ‘‘It’s impossible, but there it is!’’

“Carroll’s magnum opus thus distills and synthesizes the results of a century of factor analyses of mental tests. It is virtually the grand finale of the era of psychometric description and taxonomy of human cognitive abilities. It is unlikely that his monumental feat will ever be attempted again by anyone, or that it could be much improved on. It will long be the key reference point and a solid foundation for the explanatory era of differential psychology that we now see burgeoning in genetics and the brain sciences” (p. 5).

Technorati Tags: psychology, school psychology, educational psychology, forensic psychology, criminal psychology, cognition, clinical psychology, neuropsychology, mental retardation, MR, developmental disabilities, CHC theory, Cattell-Horn-Carroll, Gf-Gc, intelligence, IQ, IQ tests, IQ scores, capital punishment, death penalty, Arthur Jensen, Richard Snow, John Horn, Jack Carroll