Contrary to Herrnstein and Murray (1994) who claim that racial groups have different cognitive endowments and that these best explain differential test score achievements, our regression analyses document that there is less improvement in test scores per year of education for African-Americans and women. That is, the observed group test score differences do not appear to be due to racial cognitive differences but rather to other factors associated with group-linked experiences in the educational system. We found that 666 of the subjects in the Herrnstein-Murray database had actual IQ scores derived from school records. Using these as independent controls for IQ, we document that each of the test components that were the basis of the Herrnstein-Murray "IQ" scores was significantly associated with education level (p < .001). Consequently, their IQ score appears to be an education--related measure rather than an IQ test, and thus challenges the validity of their analysis.
Over the last 30 years, the use of social science data to support and evaluate social policy initiatives has become routine (Massy and Denton 1993; Wilson 1987; 1996). Proponents and opponents of welfare reform (Bane and Ellwood 1994; Katz 1997; Mead 1993), for example, have employed data to support alternative policies on welfare use and job training. It is in the area of education, however, that the interplay of research and social policy has generated the most debate. Here, social science data has been used to validate reform efforts in the teaching of mathematics and reading skills, and in support of (or opposition to) affirmative action (Arons 1997; Coleman 1989; Fischer et al. 1996; Herrnstein and Murray 1994; Kane 1998).
It is, perhaps, the issue of affirmative action that has generated the most controversy. One side asserts that affirmative action is a waste of resources because environmental interventions cannot overcome the markedly inferior cognitive endowments of certain ethnic and racial groups (Herrnstein and Murray, 1994), while the other side asserts that non-hereditary factors better explain the differential educational performance of ethnic/racial groups (Jencks and Phillips, 1998a).
Our aim here is to examine empirically the performance gap among groups and to document that one specific non-heredity factor (i.e., differential association of test score improvement with education level) offers an alternative explanation of the difference.
Genetic differences have been advanced to account for the differential educational performance of African-American and White students (Jensen 1969; 1985; Herrnstein and Murray 1994). In particular, Herrnstein and Murray (1994) have analyzed Armed Forces Qualification Test (AFQT) data from the National Longitudinal Survey of Youth (NLSY) and have concluded that "intelligence" is distributed unequally among various ethnic groups. The lower academic achievement of African-American students, according to their analyses, is owing to heredity. Indeed, they argue that there will be diminishing returns for African-Americans from the impact of additional years of education on earnings or intelligence. Therefore, social policy efforts to improve African-American students' academic achievement through more years of education or affirmative action are a waste of limited educational resources.
The social policy implications of the Herrnstein and Murray (1994) argument also apply to differences in educational performance across gender or social class. According to their analyses, women who score in the bottom 5 percent on the AFQT are inferior intellectually and are at risk for remaining unmarried, having children out of wedlock, and living in poverty. The main policy recommendation for reducing the poor economic prospects of "dull" women is that they marry and stay married (Herrnstein and Murray, 1994). …