A study by the  consulting firm Avalere Health says that consumers who bought insurance on the Affordable Care Act health exchanges last year had access to a third fewer physicians and hospitals, on average, than people with traditional employer-provided coverage.

The Washington Post said that the “provides a statistical basis for anecdotal reports from consumers and others about the more limited doctor and hospital choices in plans offered on marketplaces created by the Affordable Care Act.”

The paper notes that in these “narrow networks,” health plans “negotiate contracts with a select number of providers who agree to be reimbursed at lower rates. That means the insurers can set their premiums lower, at least theoretically. But, depending on the plan’s design, consumers typically pay more, and sometimes much more, if they use a doctor or hospital outside the network.”

The plans under the exchange  had networks with 42 percent fewer cancer and cardiac specialists; 32 percent fewer mental-health and primary-care doctors, and 24 percent fewer hospitals.

But other studies have said that patients prefer narrower networks of providers if it means lower premiums.