Depending on the arrangements between payer and provider there may be a pay-for-performance component to remuneration. This will vary across plans and payers, as will the set of targets listed in 34(b) that are reimbursement factors. For Medicare and Medicaid demonstration projects participation is voluntary. In the private insurance market, arrangements are between the provider and the payer and may include a pay-for performance element, but will vary in design.  Various payers provide incentives for quality, but the extent and breadth of the use of such incentives is not tabulated across payer types. The Center for Medicare & Medicaid Services, through the Center for Medicare and Medicaid Innovation, is testing new payment models across the country that in many cases would reward providers and institutions for improvements in quality.