Areas of Interest

• Causal inference, especially improving the estimates of treatment effects from quasi-experiments.
• Propensity score methodology.
• Intelligent tutoring systems.

Keyword Interest

• Experimental and quasi-experimental designs
• Propensity score analysis
• Selection bias
• Group-randomized trials
• Monte Carlo simulation

Current Research Topic/Field-Based Project

• Comparing the relative performance of five methods of estimating propensity scores (logistic regression, classification trees, bootstrap aggregation, boosted regression, and random forests) crossed with four types of statistical adjustments that utilize propensity scores (matching, stratification, covariance adjustment, and weighting) using simulated data.
• Collecting and summarizing the intraclass correlations (ICCs) for many health related outcomes as a resource to facilitate sample size determination for researchers planning cluster randomized trials in public health.
• Comparing the academic performance of students who used an online intelligent tutoring system, ALEKS (Assessment and Learning in Knowledge Spaces), to the academic performance of a retrospective comparison group comprised of students who took behavioral statistics under the traditional lecture format.
• Reviewing methods for assessing the adequacy of propensity score models with an emphasis on recent theoretical criteria, which do not rely on hypothesis tests of group balance on the covariates. Data from a recent quasi-experiment are used to demonstrate the methods discussed.

Former Experience

• Instructor, Psychological Statistics, The University of Memphis, 2004.
• Teaching Assistantships: Psychological Statistics and Advanced Statistics I (Regression Analysis).
• Clinical Research Coordinator, Division of Psychopharmacology, Department of Psychiatry, Vanderbilt University Medical Center, 2000-2002.
• Research Analyst III, Division of Psychopharmacology, Department of Psychiatry, Vanderbilt University Medical Center, 1998-2000.
• Psychological Examiner Intern, Mental Health Department, Tennessee State Prison for Women, 1997-1998.
• Research Assistant, Traumatic Brain Injury Program, Tennessee Rehabilitation Center, 1996-1998.

Education

• Ph.D. (2007):  Experimental Psychology, The University of Memphis
• M.A. (1998):  Clinical Psychology, Middle Tennessee State University.
• B.S.  (1994):  Psychology, University of Tennessee - Chattanooga.