Don’t count Rep. Diane Black among the supporters of the current model for accountable care organizations. The Tennessee Republican said late last week that it’s too risky for providers who wish to participate.

Unless providers can get more assurances that savings will result from participating in ACOs, “there’s going to be a lack of desire to get into the program,” Black said at a Bipartisan Policy Center forum. She added that capital-requirements for providers considering participation are excessive.

Black said the ACO program should be modified so that providers can reap benefits sooner. ACOs are an outgrowth of the new health law commonly known as Obamacare. They consist of groups of doctors, hospitals, and other healthcare providers, who give coordinated care to a designated pool of Medicare patients.

While some providers have switched ACO models due to reimbursement issues, patients in ACOs studied in a recent Harvard Medical School investigation reported higher satisfaction levels and felt their care was better coordinated, according to researchers.