Saturday, May 18, 2013

Thomas Sowell: Ethnicity and IQ

In light of the recent controversy involving The Heritage Foundations Richwine's Harvard doctoral dissertation which said that the average IQ of Hispanics and other immigrants is lower than that of the country's white "native" population and that the disparity will likely persist over generations , I offer this old but timely review of the topic from Thomas Sowell.

“Perhaps the most intellectually troubling aspect of The Bell Curve is the authors’ uncritical approach to statistical correlations. One of the first things taught in introductory statistics is that correlation is not causation. It is also one of the first things forgotten, and one of the most widely ignored facts in public policy research.” - Dr. Thomas Sowell 

Long before The Bell Curve was published, the empirical literature showed repeatedly that IQ and other mental tests do not predict a lower subsequent performance for minorities than the performance that in fact emerges. In terms of logic and evidence, the predictive validity of mental tests is the issue least open to debate. On this question, Murray and Herrnstein are most clearly and completely correct.

In thus demolishing the foundation underlying such practices as double-standards in college admissions and "race-norming" of employment tests, The Bell Curve threatens both a whole generation of social policies and the careers of those who promote them. To those committed to such policies, this may be at least as bad as the authors remaining "agnostic" (as Herrnstein and Murray put it) on the question as to whether black- white IQ differences are genetic in origin. On some other issues, however, the arguments and conclusions of The Bell Curve are much more open to dispute. Yet critics have largely overlooked these disputable points, while concentrating their attacks on either the unassailable conclusions of the book or the presumed bad intentions of the authors.