The owner checks Care Compare and sees 3 stars. A competitor across town has 4. A discharge planner mentions it. The question in the next management meeting is "what do we do this quarter to get to 4," and the honest answer involves a calendar most people have not looked at.
Home health star ratings come in two kinds, they are built from data that is many months old by the time anyone sees it, and the overall score is an average of measure ratings rounded to half stars. Understanding the math tells you which measures are worth effort and when that effort will show. This guide covers the Quality of Patient Care Star Rating in detail, the Patient Survey Star Rating briefly, and a plan for where to focus.
Two Ratings, Two Sources
CMS's Home Health Star Ratings page describes two ratings on Care Compare:
- Quality of Patient Care Star Rating, based on OASIS assessments and Medicare claims, first posted in July 2015 and updated quarterly.
- Patient Survey Star Rating, based on the Home Health CAHPS survey, first posted in January 2016 and updated quarterly. An agency needs 40 or more completed surveys over the four-quarter reporting period to receive one.
This post focuses on the Quality of Patient Care rating, because it is the one an agency's clinical operations move most directly.
The Seven Measures
The January 2027 sample provider preview report lists the seven measures:
- 1.Timely Initiation of Care
- 2.Improvement in Management of Oral Medications
- 3.Improvement in Ambulation
- 4.Improvement in Bed Transferring
- 5.Improvement in Bathing
- 6.Improvement in Dyspnea
- 7.Home Health Within-Stay Potentially Preventable Hospitalization (PPH)
CMS replaced the Acute Care Hospitalization measure with PPH effective May 2024. For every measure except PPH, higher is better. For PPH, lower is better.
To have a rating at all, an agency must have data for at least 5 of the 7 measures. For a measure to be reported, the agency needs at least 20 completed quality episodes or stays ending within the 12-month reporting period. A completed episode for the OASIS measures is a paired start or resumption of care assessment and end of care assessment. The star ratings FAQ adds that the agency must have been certified for at least 6 months, and that the outcome measures are risk-adjusted. It notes PPH is calculated only for Medicare fee-for-service patients.
The CMS page notes that since July 1, 2025 agencies must collect and submit OASIS for all patients regardless of payer, but the OASIS-based measures continue to be calculated for Medicare fee-for-service, Medicare Advantage, Medicaid and Medicaid managed care patients only.
How Far Behind the Data Runs
The January 2027 sample preview report states that the rating will appear on Care Compare in January 2027 and uses:
- OASIS-based measures for April 1, 2025 to March 31, 2026
- PPH claims data for January 1, 2025 to December 31, 2025
So the rating a family sees in January 2027 ends nine months before it is posted for OASIS measures, and a full year before for PPH. CMS sends provider preview reports about 3.5 months before posting. For the January 2027 rating, the sample report sets October 30, 2026 as the deadline to request review of a calculation error, with decisions by November 13, 2026. It also states that inaccurate OASIS recording is not a valid reason for a review request, because the conditions of participation require accurate data collection.
Two implications follow:
- A bad quarter lingers. Episodes that ended in early 2026 will keep shaping ratings until the 12-month window rolls past them.
- Improvement shows slowly. A change made in November 2026 affects episodes that end afterward, which enter ratings only as the reporting window moves forward through 2027.
The Half-Star Math
The preview report sets out the steps:
- 1.For each measure, all agencies' scores are sorted and divided into 10 roughly equal groups.
- 2.Each group gets an initial rating from 0.5 to 5.0 in half-point steps.
- 3.If an agency's score is not statistically different from the national middle categories of 2.5 and 3.0, the rating moves 0.5 toward the middle. The test is a one-sided binomial test with a p-value of 0.05.
- 4.Adjusted ratings are averaged across up to 7 measures and rounded to the nearest 0.5.
- 5.A final step maps the rounded average to stars: 0.5 becomes 1 star, 2.5 becomes 3 stars, 3.0 becomes 3.5 stars, 3.5 becomes 4 stars, 4.0 becomes 4.5 stars, and 4.5 or 5.0 becomes 5 stars.
Worked Example: What It Takes to Move Half a Star
These measure ratings are illustrative, not from any real agency.
- Timely Initiation of Care: 4.0
- Oral Medications: 3.0
- Ambulation: 2.5
- Bed Transferring: 3.5
- Bathing: 2.0
- Dyspnea: 3.0
- PPH: 3.5
Sum 21.5, average 3.07, rounded to 3.0, final rating 3.5 stars.
Now raise Bathing from 2.0 to 3.0. Sum 22.5, average 3.21, still rounds to 3.0. Still 3.5 stars. One measure moving a full point did nothing visible.
Raise both Bathing and Ambulation to 3.5. Sum 24.5, average exactly 3.5, final rating 4 stars.
The lesson: because the overall score is an average rounded to half points, small gains on one measure often vanish. Plan for coordinated improvement across related measures, and know where your agency sits relative to the rounding thresholds before choosing targets.
Where Operational Effort Shows Up
Timely Initiation of Care. CMS's process measures table defines it as the percentage of quality episodes in which the start or resumption of care was on the physician-ordered date if one was provided, otherwise within 2 days of the referral date or inpatient discharge date, whichever is later. It uses OASIS items including M0102, M0104, M0030, M0032 and M1005. This is an intake and scheduling measure as much as a clinical one, and accurate dates on the OASIS decide it.
The four functional improvement measures (ambulation, bed transferring, bathing, dyspnea) compare start or resumption of care with discharge. The OASIS-E2 Guidance Manual includes a worked dyspnea calculation in its appendix showing how episodes where the patient was not short of breath at start of care are excluded. Accurate scoring at both ends matters; so does a care plan aimed at those functions.
Improvement in Management of Oral Medications links to M2020 and to the teaching and reconciliation work covered in the medication reconciliation guide.
PPH reflects hospitalizations that might have been prevented during the stay. It responds to early identification of decline, follow-up after medication changes, and clinician review of risk.
A 90-Day Plan
- 1.Pull your latest preview report and Care Compare data. Note each measure's group rating and how far your average sits from the next rounding threshold.
- 2.Check Timely Initiation first. Audit 20 recent starts of care for date accuracy and the gap between referral and visit. The referral management guide covers intake bottlenecks.
- 3.Audit OASIS accuracy at both ends. Run start of care and discharge scoring reviews on the functional items. The OASIS-E2 changes post lists where E2 rework is concentrated.
- 4.Pick two related measures. Bathing and bed transferring often share interventions. Set targets for both.
- 5.Use your Review and Correct reports. The preview report notes they let agencies find and amend OASIS submission errors in a timely way, before data freezes.
- 6.Track monthly, report quarterly. Your internal numbers will lead Care Compare by months. Do not wait for the public rating to tell you whether a change worked.
Read the Ratings From Your Own Records
Waiting for Care Compare means steering by a mirror that is nine months old. Nuraflow is being designed so that reports and analytics calculate from current source records, and quality assurance routes OASIS and documentation issues to named reviewers before completion or submission.
This article is general information. Star rating methodology can change; check the current CMS methodology, preview report and FAQs before setting targets.