This study introduces an evidence-centered approach to reverse design for languages for specific purposes (LSP) courses called domain analysis. The article describes the research framework and its potential to provide consistent empirical rigor to the necessarily decentralized field of LSP by reporting on one study using domain analysis in the legal Spanish context. The research questions examine the parameters of the domain under study--legal Spanish for law students at one university--and the target functional outcomes for those students. The results included parameters that were limited to public interest law in the U.S. context. Eight topic areas emerged as central to that context and functional outcomes were identified for reading, listening, and speaking. Though sight translation was a necessary skill, writing was not needed in the domain.