Teaching note for cases 916026 and 916040. The pharmacy benefit manager (PBM) sector processes prescription drug claims on behalf of companies that offer a prescription drug benefit to their employees. The case associated with this teaching note follows Bob Nease, Chief Scientist at Express Scripts, as he considers methods to promote home delivery of prescription drugs by mail-a process proven to lower prescription fill error rates, increase cost savings, and improve medication adherence. The teaching note explains how an instructor can use the case to lead a discussion regarding the use of behavioral economics ideas, especially the principles of choice architecture, to change the behavior of large groups of people at low cost.