Our interests span modern psychometric methods (e.g., item response theory), cognition and intelligence, and quantitative methods. A main research program has been to integrate cognitive theory into psychometric models and test design. To this goal, we have been developing new item response theory models and conducting empirical research on the cognitive basis of an individual's responses. Recently, this effort has lead to the exciting possibility of "tests without items". That is, items are automatically generated by artificial intelligence to target levels and cognitive sources of difficulty to optimally measure each individual examinee during testing. The measurement areas have included fluid reasoning, spatial ability, mathematical reasoning, mathematical achievement and verbal comprehension.