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…

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…

The author replies to Jensen and Vernon's article and maintains that there is little reason for accepting Jensen's claims, particularly with respect to the major theoretical question. (Author/LMO)

Comments on some methodological limitations of the research base of "The Bell Curve": blind use of the normal distribution (bell curve); avoidance of nonnormal statistical distributions, which are more appropriate for some social and economic characteristics; copious use of percentiles and quintiles, inappropriate with nonnormal…

Four points are made in regard to the controversial reaction times studies: (1) apparatus used is not the best; (2) practice effects have not been thoroughly accounted for; (3) there is some evidence that simple reactions are different from choice ones; and (4) basic data to be explained are those which show substantial group differences.…

The pattern of parent-child correlations in adoption studies has long been interpreted to suggest substantial additive genetic variance underlying variance in IQ. The studies have frequently been criticized on methodological grounds, but those criticisms have not reflected recent perspectives in genetics and developmental theory. Here we apply…

Data of Skodak and Skeels (1949) are reinterpreted to suggest that at least one-third of the reported advantage of adopted children's intelligence quotients (IQ) over adoptive mothers is an artifact of the IQ test norms. The children's mean IQ could easily be higher than the estimated figures usually quoted. (SLD)

Longstreth's critique of Jensen's research on the relationship of IQ to individual differences in visual reaction time (RT), measured in the Hick paradigm, is said to have numerous errors of fact and interpretation, some trivial and some of theoretical importance. (Author/LMO)

A critique by Carroll of a study by Jarman and Das (EJ 171 820) is refuted in terms of the methodology and theory of the Jarman and Das study. Additionally, two general issues concerned with individual differences in cognitive processes and strategic behavior are elaborated beyond Carroll's discussion. (Author/CP)

Criticizes data analysis and interpretation in "The Bell Curve:" Herrnstein and Murray do not actually study the "cognitive elite"; do not control for education when examining effects of cognitive ability on occupational outcomes, ignore, cultural diversity within broad ethnic groups (Asian Americans, Latinos), ignore gender…

This author reviews published data and presents new data relevant to the Spearman hypothesis concerning racial differences on cognitive tests. He concludes that across-the-board difference between SES groups occurs primarily on the general factor, and that there are major determinants of race differences independent of the general factor.…

The author responds to criticisms made by Jensen pertaining to tests of the Spearman hypothesis. The near-zero correlation between Blacks and low socio-economic status Whites is neither an artifact of methodology nor a sampling fluke. Low and high SES White differences are highly correlated with general factor loadings. (LMO)