Questions: Third-party payers often adopt payment systems and fee schedules after has implemented them.

The answer is Medicare.

Medicare is a federal health insurance program in the United States primarily for people aged 65 and older, but also for some younger individuals with disabilities. It is often a trendsetter in the healthcare industry, implementing new payment systems and fee schedules that other third-party payers, such as private insurance companies, often adopt later. This is because Medicare's policies can significantly influence the healthcare market due to its large size and regulatory power.

While Medicaid is another major government program, it is state-administered and often follows federal guidelines. However, it is not typically the primary source of new payment systems that third-party payers adopt.

Private insurance companies may develop their own payment systems, but they often look to Medicare for established models due to its comprehensive data and influence.

The Veterans Health Administration (VHA) provides healthcare services to eligible military veterans. While it has its own systems, it does not typically set trends for third-party payers in the broader healthcare market.