Methods: Plans list the drugs they cover in "formularies."

Some of the data in the GoodRx analysis came from the Centers for Medicare and Medicaid Services. The rest of the formulary data came from Managed Markets Insight and Technology.

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The analysts developed a theoretical commercial "best plan" by listing all of the drugs that at least one of the commercial plans covers.

The analysts determined what percentage of drugs a commercial plan covers by dividing the number of medications in each commercial plan's formulary by the total number of medications covered by the theoretical "best commercial plan."

The analysts then weighted each commercial plan's drug coverage percentage by plan enrollment and averaged the enrollment-weighted drug coverage percentages.

The analysts used a similar process to calculate the percentage of the drugs covered by a commercial plan that are subject to access restrictions, such as preauthorization review requirements or quantity limits.

The analysts took the same steps to calculate drug coverage percentages and access restriction percentages for Medicare plans and Medicaid plans.

The analysts did not distinguish between employer-sponsored commercial coverage and individual commercial health coverage, but the commercial plan coverage includes employer plans.

Commercial plans vs. the rest: Commercial plans provide more ready access to drugs than Medicare or Medicaid plans because they are less likely to apply access restrictions.

The average commercial plan covers 79% of the drugs that the theoretical best plan covers, compared with a coverage percentage of 56% at Medicare plans and 97% at Medicaid plans.

But commercial plans apply access restrictions to just 35% of the drugs they cover. The percentage of covered drugs subject to access restrictions is 49% at Medicare plans and 63% at Medicaid plans.

Philosophy: Tori Marsh and and Trinidad Cisneros, the analysts who prepared the analysis, assume as a given that providing access to the maximum number of drugs without imposing access restrictions is the ideal.

"For many Americans, the real hurdle to treatment isn't just medication prices," the analysts write. "It's navigating the complex policies embedded in their health plan that dictate the cost they pay at the pharmacy counter."

Some patients who face access restrictions may end up not using any medication, the analysts warn.

Advocates of access restrictions argue that well-designed utilization management efforts can protect plans against drugs that are too expensive and patients against drugs that are too expensive or too likely to cause side effects that are worse than the conditions being treated.

What it means: Employers and benefits advisors could use a simpler version of the GoodRx approach to summarize how tightly a given plan manages access to medications.