The California workers’ compensation Official Medical Fee Schedule is based upon a “pay for procedure” model which encourages medical professionals to provide as many procedures as possible to increase income. The next evolution of payment for medical services is known as “pay for performance.” Under this new model medical professionals will be paid more money for better outcomes, rather than for procedures that have little or no effect on outcome.

Changing the way it does business, Medicare on Friday unveiled a far-reaching overhaul of how it pays doctors and other clinicians consistent with the “pay for performance” model.

The goal is to reward quality, penalize poor performance, and avoid paying piecemeal for services. Whether it succeeds or fails, it’s one of the biggest changes in Medicare’s 50-year history.

The complex regulation is nearly 2,400 pages long and will take years to fully implement. It’s meant to carry out bipartisan legislation passed by Congress and signed by President Barack Obama last year.

The concept of paying for quality has broad support, but the details have been a concern for some clinicians, who worry that the new system will force small practices and old-fashioned solo doctors to join big groups. Patients may soon start hearing about the changes from their physicians, but it’s still too early to discern the impacts.

The Obama administration sought to calm concerns Friday. “Transforming something of this size is something we have focused on with great care,” said Andy Slavitt, head of the federal Centers for Medicare and Medicaid Services.

Officials said they considered more than 4,000 formal comments and held meetings around the country attended by more than 100,000 people before issuing the final rule. It eases some timelines the administration initially proposed, and gives doctors more pathways for complying.

The American Medical Association said its first look suggests that the administration “has been responsive” to many concerns that doctors raised.

In Congress, staffers were poring over the details. Rep. Tom Price, R-Ga., who worries that Medicare’s new direction could damage the doctor-patient relationship, said he’s going to give the regulation “careful scrutiny.” Sen. Orrin Hatch, R-Utah, chairman of a panel that oversees Medicare, called it an “important step forward,” but said the administration needs to keep listening to concerns.

MACRA, the Medicare Access and CHIP Reauthorization Act, creates two new payment systems, or tracks, for clinicians. It affects more than 600,000 doctors, nurse practitioners, physician assistants and therapists, a majority of clinicians billing Medicare. Medical practices must decide next year what track they will take.

Starting in 2019, clinicians can earn higher reimbursements if they learn new ways of doing business, joining a leading-edge track that’s called Alternative Payment Models. That involves being willing to accept financial risk and reward for performance, reporting quality measures to the government, and using electronic medical records.