In 2010, Abadie, Diamond and Hainmueller used the synthetic control method to analyze a cigarette tax implemented in California in 1988. Since then, this method has been increasingly popular, with the original article garnering more than four thousand citations. Part of the synthetic control method’s popularity comes from its ability to analyze a treatment or policy that was applied to a single area, or where there are no obvious areas that can be used as controls. It does this by creating a synthetic control, formed by weighting together control areas drawn from a pool of potential candidates. In this brief we review the method, its necessary assumptions, and how they apply to the cigarette study. In a related report, we provide a step-by-step guide for its use.