This course introduces the principles and practice of linear regression modeling. Underlying model assumptions are reviewed and scrutinized. In intensive computer laboratories, statistical tools for creating appropriate data structures and estimating models using real data are presented and guidance is provided in interpretation of model parameters. The remainder of the course focuses on causal inference and the potential outcomes framework. Panel data models and statistical tools for their estimation are presented, and their potential to improve causal inference are compared. Discussion is extended to consider natural experiments and instrumental variable approaches to causal inference. The sensitivity of estimates to violations of model assumptions are evaluated, with special attention given to methods centering on computer simulation.