My research interests include mathematical and statistical aspects of psychological measurement theory; statistical genetics; applied cognitive psychology; and technology transfer focused on early mathematics education. Some practical applications of my work are: estimating the number of heroin addicts in the United States; analyzing the processes of verbal memory storage and retrieval; and studying genetic and environmental influences in complex mental illness. Recently, my research has focused on prenatal factors that increase risk for schizophrenia and developing multimedia approaches for teaching quantitative concepts and skills to young children.