Abstract: “Big data” has become the ubiquitous watchword of this decade. Predictive analytics, which is something we want to do with big data -- to use of electronic algorithms to forecast future events in real time. Predictive analytics is interfacing with the law in a myriad of settings: how votes are counted and voter rolls revised, the targeting of taxpayers for auditing, the selection of travelers for more intensive searching, pharmacovigilance, the creation of new drugs and diagnostics, etc. In this paper, written for the symposium “Future Proofing the Law,” we want to engage in a bit of legal arbitrage; that is, we want to examine which insights from legal analysis of predictive analytics in better-trodden ground — predictive policing — can be useful for understanding relatively newer ground for legal scholars — the use of predictive analytics in health care. To the degree lessons can be learned from this dialogue, we think they go in both directions.