CMS launched star ratings Thursday on its Hospital Compare website as a way to streamline hospital ratings for patients trying to make healthcare decisions.
The ratings are based on a five-star scale, with one being the lowest rating and five being the highest rating of excellence and quality. CMS will publish 12 different star ratings on the Hospital Compare website for each facility: 11 of the ratings will be based on individual HCAHPS measures and the 12th is a composite star rating.
Here are five things to know about how the star ratings are calculated.
1. To be eligible, hospitals are required to have a minimum of 100 HCAHPS questionnaires completed within four quarters and be eligible for public reporting of HCAHPS measures. Those facilities that do not meet the 10-survey minimum do not have enough data to receive star ratings, but their scores on the survey will still be published on the Hospital Compare site.
2. For eligible facilities, CMS converts survey responses to a linear scale from zero to 100. Negative survey responses such as "never," "no," "definitely no," "strongly disagree," and "overall rating 0" receive a zero on the linear scale. The most positive responses receive 100 points on the scale: "always," "yes," "definitely yes," "strongly agree," and "overall rating 10." Responses move up the scale incrementally based on the number of possible answers. For example, responses on a scale of "never," "sometimes," "usually," and "always" would score 0, 33.3, 66.6, and 100 respectively.
3. Linear scores are adjusted based on three factors — patient mix, survey mode and quarterly weight — and rounded to whole integers. The patient mix adjustment helps level scores based on patient characteristics, as some patient sub-groups may be more or less likely to answer the survey in certain ways. The survey mode adjustment accounts for the medium through which patients completed the survey, whether it is by mail, telephone or interactive voice response. The scores are also weighted by the number of eligible patients discharged per quarter. Four-quarter linear score averages are rounded to integers.
4. CMS uses a clustering algorithm to covert the linear scores into star ratings. This is the same algorithm CMS uses for their Medicare Part C and Part D rating. Only whole stars are assigned based on a mathematical algorithm that groups score into clusters so that hospitals receiving scores within the same cluster are as similar as possible and those within different clusters are as different as possible, according to HCAHPS. The cut off points vary based on each measure. An example of the cutoff points for scores between Quarter 4 in 2013 and Quarter 3 in 2013 can be found here in Appendix C.
5. The 12th composite star rating is an average of the other ratings. The summary rating takes the average of the seven HCAHPS composite measures, a combined rating for HCAHPS individual items and a combined rating for the HCAHPS global items. The seven composite measures are communication with nurses, communication with physicians, hospital staff responsiveness, pain management, communication about medicines, discharge information, and care transition. The individual items are averaged into one score and include the environmental factors of cleanliness and quietness. The global items are also averaged into one score and include the overall hospital rating and whether the patient would recommend the hospital. The final averages are rounded to full star ratings.
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