Classification procedures are common and useful in behavioral, educational, social, and managerial research. Supervised classification techniques such as discriminant function analysis assume training data are perfectly classified when estimating parameters or classifying. In contrast, unsupervised classification techniques such as finite mixture…

Despite several decades of research suggesting the importance of both genetic and environmental factors, these findings are not well integrated into the larger educational literature. Following a discussion of quantitative and molecular genetic methods, this article reviews behavioral genetic findings related to cognitive and academic skills. This…

Insights into learning disabilities can result from adopting the Piagetian perspective. Although significant contributions have been made by taking a psychometric view of learning disabilities, these contributions are limited because the psychometric view focuses on quantifiable differences in functioning, the end product of thinking, and the…

Chapter 5 of "Education of Exceptional Children, a review of the literature for the 3-year period since the issuance of "REVIEW OF EDUCATIONAL RESEARCH, Volume 36, No. 1, February 1966.