In recent years, numerous state and federal courts have heard challenges to legislative redistricting maps on partisan grounds. How do we determine whether a redistricting plan was intentionally drawn to favor one party or another? In this presentation, Jowei Chen discusses his work using computer simulation models to produce thousands of partisan-neutral maps for congressional and state legislative districts. He analyzes how states’ enacted districting maps compare to these computer-simulated maps along traditional redistricting criteria and along partisanship. These comparisons have been used to help courts evaluate whether redistricting maps exhibit partisan bias.