Motivated by the context of opioid policy research, this workshop will provide an overview of key methodological challenges faced when evaluating the effectiveness of state-level policy using annual state- level data, as well as potential solutions and practice guidelines. We will begin discussing the commonly used linear difference-in-difference (DID) model and then subsequently discuss DID extensions and alternative approaches (i.e., autoregressive models, non-linear models, doubly robust methods, synthetic controls). Methods will be demonstrated in STATA using an opioid policy case study.