There are three major distribution channels for pchA tools. Doctors can prescribe them, payers can provide them as part of wellness or disease management services, and people can buy them over the counter. A variety of barriers impact these channels. This chapter concentrates on barriers external to the individual and relevant for stakeholder action. The five key areas of external barriers to widespread use of pchA are illustrated in Figure 14.1. These five Ps include Physicians, Payment, Proof, Pleasing the customer, and Privacy. In the illustration, they are embedded within a brick wall that people and stakeholders need to chip away at to advance the widespread adoption pchA.