In this commentary of "Evaluating the Gifted Program of an Urban School District Using a Modified Regression Discontinuity Design" by Davis, Engberg, Epple, Sieg, and Zimmer, we examine the background of the study, critique the methods used, and discuss the results and implications. The study used a fuzzy regression discontinuity design…

Crude and dangerous ideas about the genetic heritability of intelligence, and a supposed biological basis for the Black/White achievement gap, are alive and well inside the education policy process but taking new and more subtle forms. Drawing on Critical Race Theory, the paper analyses recent hereditarian writing, in the UK and the USA, and…

Because of the Flynn effect, IQ scores rise as a test norm ages but drop on the introduction of a newly revised test norm. The purpose of the current study was to determine the impact of the Flynn effect on learning disability (LD) diagnoses, the most prevalent special education diagnosis in the United States. Using a longitudinal sample of 875…

Lynn (2010) suggests that differences in average intelligence explain many of the differences observed across the Italian regions. This paper puts forward a methodological critique to his study, coupling it with an empirical test showing that Lynn's analysis is not sufficiently robust to support its conclusions. (Contains 2 tables.)

Beraldo (2010) and Cornoldi, Belacchi, Giofre, Martini, and Tressoldi (2010) (CBGMT) have eight criticisms of my paper (Lynn, 2010) claiming that the large north-south differences in per capita income in Italy are attributable to differences in the average levels of intelligence in the populations. CBGMT give results for seven data sets for IQs in…

Working with data from the PISA study (OECD, 2007), Lynn (2010) has argued that individuals from South Italy average an IQ approximately 10 points lower than individuals from North Italy, and has gone on to put forward a series of conclusions on the relationship between average IQ, latitude, average stature, income, etc. The present paper…

A brief discussion of theories of general intelligence precedes a report of relevant empirical data. Results from the factor analysis of more than 20 sets of Wechsler Adult Intelligence Scale (WAIS) data indicate that the WAIS clearly is not a one-factor scale. It does not measure a single, general intelligence. Roughly 17 percent of the reliable…

This paper critically examines the portions of Arthur Jensen's books, "Genetics and Education" and "Educability and Group Differences," that concern Barbara Burks' 1928 study of adoptive families. Jensen cites the low correlations of children's IQs with measures of home environment from Burks' study as evidence that environment…

Criticizes "The Bell Curve" for its lack of understanding of the philosophical nature of intelligence (and mind). Points out that various philosophical attempts to analyze the concept of intelligence are routinely ignored by empirical workers in the field of IQ testing because such philosophical work makes obvious the lack of connection…

Data from Terman's "Genetic Studies of Genius" (1925-1959) relating to sample size, mean IQ, and variance of IQ scores were analyzed in terms of their conformation to the theoretically projected statistics derived from a consideration of the normal curve. (Author/RC)

Methodology texts argue and many researchers may believe that normality of distribution is a sufficient condition for inferring that interval scale measurement has been achieved. It has also been argued that ordinal measurements cannot be normally distributed. Counter examples and a general result show such reasoning to be fallacious. (Author/RH)

Written in response to an article (Horn, 1983) that appeared in special Developmental Behavioral Genetics section of CHILD DEVELOPMENT (Volume 54), this commentary (1) notes some issues concerning Horn's analysis and interpretation of data and (2) highlights the potential for interpretational bias in behavior genetics research. (Author/BE)

In this rebuttal to Walker and Emory's commentary (also in this issue), Horn argues that the issue of the influence of environment on the average IQ of adopted children was well discussed in his article (Volume 54 of CHILD DEVELOPMENT). (BE)

The author examines and rebuts arguments advanced by Michael Matthews, a Marxist critic of intelligence testing and IQ research. Arthur Jensen's views on the nature, heritability, and social importance of IQ are defended. (BS)

Criticizes and examines the motives behind Charles Murray's "The Bell Curve." Murray's book claimed that many social problems, including crime and poverty among blacks, could be explained by African Americans' lack of intelligence as evidenced by testing. Reveals the book's skewed methodology as well as its interest-guided financial…