social class, income, education, generation of immigration, family structure, and geographical region is not captured by the racial/ethnic designation. Phinney goes on to note that “ethnicity cannot be treated like an independent variable that explains an outcome” (p. 924), yet that is precisely what is sought when one examines the bivariate relationship between ethnicity and disability status. In the case of biracial children, the confound is even more severe, as there has not been a “mixed” box for parents to check and a child is forced into one of the extant boxes, suggesting that “everyone in the category belongs completely in that box” (Hodgkinson, 1995:175).
Disability Status. In both the OSEP and OCR surveys, the disability status (i.e., the specific disability category) of a child is, in the vast majority of cases, taken directly from school records—that is, the children are “school identified” as qualifying for special education by virtue of qualifying for a specific disability category. In traditional epidemiological studies, the concepts of prevalence (total number of cases at a given point in time) and incidence (number of new cases) are employed. The figures reported in the surveys considered here are assumed to be prevalence figures; however, there is a lack of precision in the school’s ability to detect “true” cases of disability, particularly in the judgmental categories. Stated differently, we do not know what the true prevalence of these conditions would be if specific criteria were applied rigorously in screening the population of children.
As a result, there are many false positives and false negatives in identification, introducing error of an unknown size (but known to be substantial, particularly in the LD area) (see Gottlieb et al., 1994; MacMillan et al., 1998a; Shaywitz et al., 1990; Shepard et al., 1983). Comparability across states is difficult, in part, because the states have differing criteria for eligibility. Mercer et al. (1996) surveyed state criteria for defining LD particularly in the method for calculating discrepancy (i.e., standard score discrepancy vs. regressed discrepancy) and the magnitude of the aptitude-achievement discrepancy (e.g., 1 SD, 1.5 SDs) required. Frankenberger and Fronzaglio (1991) and Denning et al. (2000) analyzed state guidelines for defining mental retardation and again reported considerable variability. On the criterion of intellectual level, Denning et al. (2000) reported that 13 states have no IQ cutoff score, Ohio and Pennsylvania use IQ 80 as the cutoff score, while most set the IQ cutoff score at IQ 70 or –2 SDs.
Giftedness. The issues plaguing the assignment of disability status also contaminate the collection of data on children identified as gifted and talented. The lack of national legislation governing the definition of, or services for, gifted and talented students has left each state with the pre-