The Department of Veterans Affairs has for years assigned star ratings for each of its medical centers based on the quality of care and service they provide, but the agency has repeatedly refused to make them public, saying they are meant for internal use only.

USA TODAY has obtained internal documents detailing the ratings, and they show the lowest-performing medical centers are clustered in Texas and Tennessee.

VA hospitals in Dallas, El Paso, Nashville, Memphis and Murfreesboro all received one star out of five for performance as of June 30, the most recent ratings period available.

Many of highest-rated facilities are in the Northeast — in Massachusetts and New York — and the upper Midwest, including in South Dakota and Minnesota. Those medical centers scored five out of five stars.

The VA determines the ratings for 146 of its medical centers each quarter and bases them on dozens of factors, including death and infection rates, instances of avoidable complications and wait times.

USA TODAY Network is publishing the ratings in full for the first time so that members of the public — including patients and their families — can see how their local VA medical centers stack up against others across the country.