After several months of buildup, the CMS Hospital Compare website began to offer overall hospital star ratings July 27.

A blog post by the agency explained the program as a way to quickly and uniformly compare potential hospitals. The system is meant to “help millions of patients and their families learn about the quality of hospitals, compare facilities in their area side-by-side, and ask important questions about care quality when visiting a hospital or other healthcare provider,” wrote Director of the Center for Clinical Standards and Quality Kate Goodrich, MD, MHS.

The ratings come in categories of one through four stars. They’re an average of 64 total measures used to judge the hospitals, such as hospital-acquired infections, overall death rates and readmission rates.

CMS touts the system as a way to offer at-a-glance, big-picture views of hospitals. Previous reports by the agency showed that the number of hospitals receiving each level of rating followed an expected statistical distribution, even when stratified by different classifications, such as teaching versus non-teaching hospitals.

Beyond making patient decisions easier, the rollout has also been touted as an ethical step in promoting transparency as part of the Obama Administration’s Open Data Initiative.

Some critics in Congress and the healthcare industry have said the rating doesn’t allow patients to prioritize certain metrics over others. Also, hospitals in lower-income areas tend to have lower scores, which might indicate a deficiency with the rating system itself.

According to a July 27 statement by CMS, the ratings reflect solutions meant to address those concerns. The agency hosted two feedback calls with representative from more than 4,000 providers across the country and opened the system to a public comments period, including a “dry-run” rehearsal period last summer.

CMS said the concerns over different kinds of hospitals receiving disparate ratings are unnecessary:

“CMS designed the methodology to be inclusive of as many hospitals and as many measures as possible. This approach prevents the methodology from limiting star rating calculations to certain types of hospitals based on characteristic or size,” the statement said.

Goodrich pointed out that some of the methodologies have already been adjusted to reflect the socioeconomic differences among patient populations and how those could affect the hospitals’ ratings. She said that adjustment will continue as deemed necessary by the National Quality Forum, the assistant secretary for planning and evaluation and requests by providers.  

Plus, the ratings were weighted using input from a panel of three experts who reviewed the ratings criteria “based on clinical guidelines” and subjected them to rigorous scientific review and testing,” Goodrich said.

CMS’s statement included a commitment to continue to review the star rating guidelines and to update or improve them quarterly.