Statistics and Data Science Seminar
Dr. Yili Pritchett
Abbott Laboratories
An Application of Path Analysis in the Design of Clinical Trials
Abstract: Path analysis, first developed in the field of genetics and actively used in sociology, refers to a modeling approach for causal relationships (Wright, 1934). In the setting of clinical research, path analysis can be a useful tool to demonstrate an independent treatment effect on a disease state, which might have causal relationships with other disease states that can be treated by the same therapy. In this presentation, the idea of using path analysis in clinical trial design will be introduced. In this approach, pre-specified causal relationships can be modeled by structural equations so that the treatment effect on the disease state of interest (direct effect) will be tested after accounting for the treatment effects on the other conditions (indirect effects). The total treatment effect can be decomposed as the sum of the direct and the indirect effects, and the statistical significance of each effect can be tested. The idea and the approach will be illustrated by concrete examples where an antidepressant was investigated for its effect on the management of different types of pain. Further statistical discussions will be given on the topics of the invariance between ordinary linear regression and standardized linear regression, and the generalization from ordinary linear model to generalized linear model.
Wednesday April 16, 2008 at 3:30 PM in SEO 712