My primary interests continue to be the application of latent variable measurement models, including structural equation (SEM) and item response theory (IRT) to personality, psychopathology and health outcomes measures. I am not particularly interested in the mathematical/statistical machinery underlying these models, but rather in their utility to ultimately inform substantive theory. My current projects span a wide scope and include: (a) the development of new algorithms to find complex latent structure in item response data and to differentiate among hierarchical models, (b) using MIMIC modeling to validate latent variables as reflecting underlying, systematic, neuro-psychological causes, and (c) the development and implemenation of new person-fit or case influence statistics to be used to evaluate SEM measurement models. This latter project is an extension on my previous person-fit work and is consistent with my view that for any psychological phenotype (e.g., ADHD) different latent structures may applies to different subsets of individuals. For example, for some individuals ADHD symptoms may cohere in simple way suggesting a single bio-psychological process, while for others a two-factor model may be more appropriate.