CMS Star Rankings

A web-based tool for calculating and exploring CMS Hospital Star Ratings, replicating the official SAS methodology (July 2025). Data here: https://qualitynet.cms.gov/inpatient/public-reporting/overall-ratings/sas

Overview

This project converts the official CMS SAS code for Hospital Star Ratings into a modern Python implementation wrapped in a Flask web application. It allows users to:

• Browse and search for hospitals.
• View detailed quality measures for specific hospitals.
• Calculate Star Ratings dynamically based on input measures.
• Visualize the breakdown of scores across different measure groups (Mortality, Safety of Care, Readmission, Patient Experience, and Timely & Effective Care).

The calculation logic is a direct port of the Yale CORE SAS Package (July 2025), ensuring accuracy with official CMS methods.

Prerequisites

• Python 3.8 or higher
• pip (Python package installer)

Installation

1. Clone or download this repository.
2. Navigate to the project directory:

   cd "CMS Star Rankings"

3. Set up a virtual environment (optional but recommended):

   python -m venv .venv
   source .venv/bin/activate  # On Windows use: .venvScriptsactivate

4. Install the required Python packages:

   pip install -r star_ratings_app/requirements.txt

Usage

1. Navigate to the application directory:

   cd star_ratings_app

2. Run the application:

   python calculations.py

3. Open your web browser and go to:
   http://localhost:5555

Project Structure

• star_ratings_app/: Contains the Flask application source code.
  • calculations.py: Main application logic, including the Star Rating algorithm and Flask routes.
  • index.html: Frontend user interface.
  • script.js: Client-side logic for interactivity and API communication.
  • style.css: Application styling.
  • requirements.txt: Python dependencies.
• alldata_2025jul.csv: Source data file containing hospital measures (located in the root directory).
• Hospital_General_Information.csv: Source data file containing hospital names and general info (located in the root directory).

Methodology

The application implements the following steps from the CMS methodology:

1. Standardization: Converting raw measure scores to Z-scores using national means and standard deviations.
2. Grouping: Categorizing 46 measures into 5 groups (Mortality, Safety, Readmission, Patient Experience, Process).
3. Weighting: Applying standard weights to group scores.
4. Clustering: Using K-means clustering to determine star rating cutoffs (1-5 stars) based on summary scores within peer groups.

License

See the LICENSE file for details.

Imported from gh:Kentucky-Open-Science/CMS-Star-Rankings. Source last updated 2026-01-16. Synced 2026-07-27.