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30-day mortality rate
The share of patients admitted for a specific condition who died within 30 days, counted wherever the death occurred — including at home or in another facility.
Why it matters: The window deliberately extends past discharge. A hospital cannot improve its figure by discharging unstable patients, because deaths after they leave still count. Lower is better. Most hospitals land in the "no different than the national benchmark" band, which is a normal result rather than a mediocre one.
C
C. diff Clostridioides difficile
An intestinal infection causing severe diarrhoea, most often after antibiotic treatment has disrupted normal gut bacteria.
Why it matters: Rates are influenced by how carefully a hospital prescribes antibiotics as well as by cleaning practice, which makes this measure a reasonable signal of antibiotic stewardship.
Care Compare
The official CMS tool at medicare.gov that publishes quality data for hospitals, nursing homes, dialysis facilities and other providers.
Why it matters: This is the authoritative source for everything on this site. We explain the data and add context; Care Compare is where to verify it, and where to go if our figures and theirs disagree.
CAUTI Catheter-Associated Urinary Tract Infection
A urinary tract infection linked to the use of a urinary catheter.
Why it matters: The main preventive measure is not using a catheter longer than necessary, so this figure partly reflects how carefully a hospital reviews whether each catheter is still needed.
CCN CMS Certification Number
A six-character code CMS assigns to every Medicare-certified hospital. It identifies the facility in every federal dataset.
Why it matters: This is the most reliable way to confirm you are looking at the right hospital. Names change after mergers and several hospitals in one state can share a name, but the CCN does not move. We show it on every hospital page so you can look the same facility up on Care Compare and compare like with like.
Charity care
A hospital's programme for reducing or writing off bills for patients who cannot afford them. Non-profit hospitals must offer one to keep their federal tax exemption.
Why it matters: Hospitals are required to have a written financial assistance policy but are not required to advertise it, and many eligible patients never apply because nobody mentions it. Eligibility often extends well above the poverty line — some programmes reach several times it. Ask for the financial assistance policy in writing before you agree to a payment plan, because a plan is debt and assistance is not.
CLABSI Central Line-Associated Bloodstream Infection
An infection that enters the bloodstream through a central line — a catheter placed in a large vein, usually in the neck, chest or groin.
Why it matters: These infections are serious and largely preventable through sterile insertion technique and prompt line removal, which is why CMS tracks them as a safety measure. Reported as a standardized infection ratio rather than a count.
Critical access hospital
A small rural hospital with 25 or fewer inpatient beds, located at a distance from other hospitals, paid by Medicare under a separate cost-based system.
Why it matters: These hospitals rarely have star ratings or complete measure sets — they treat too few patients for the statistics to be reliable, and CMS excludes them from the star rating programme by design. That absence says nothing about the care. For many rural communities a critical access hospital is the difference between 20 minutes to emergency care and two hours.
E
EMTALA Emergency Medical Treatment and Labor Act
A 1986 federal law requiring any hospital with an emergency department that accepts Medicare to screen and stabilize anyone who arrives with an emergency, regardless of ability to pay or insurance status.
Why it matters: This is the single most important thing to know about emergency care in the United States. An emergency department cannot turn you away, delay treatment to check your insurance, or transfer you before you are stable. It applies whether or not you have insurance, and whether or not you are a citizen. It does not make the care free — you can still be billed.
Excess days in acute care EDAC
Days patients spent back in hospital care per 100 discharges, compared with what was expected. A negative number means fewer days than expected.
Why it matters: It is a fuller picture than a yes/no readmission count, because it distinguishes a brief emergency visit from a two-week readmission. Negative is good, which is the opposite of most people's instinct when reading a negative number.
F
Footnote
A code CMS attaches to a measure to explain why no result was published — most often that there were too few cases to report reliably.
Why it matters: This is why we show a reason instead of an empty cell. A blank looks like concealment; "fewer than 25 cases, so results are not reported" is both the truth and far less alarming.
H
HCAHPS Hospital Consumer Assessment of Healthcare Providers and Systems
A standardized survey sent to a random sample of adult patients between 48 hours and six weeks after they leave the hospital. Every hospital asks identical questions in identical wording.
Why it matters: It is the only part of the data that comes from patients rather than claims. The published figure counts only patients who answered "always" — a deliberately high bar, so 70% is genuinely good rather than a failing grade. It measures communication and environment, not clinical outcomes, so read it alongside the mortality and safety measures rather than instead of them.
Hospital ownership
Who owns the hospital — a non-profit organization, a for-profit company, or a government body at federal, state or local level.
Why it matters: Ownership does not predict quality in any simple direction, and the research is genuinely mixed. What it does affect is behaviour around money: non-profit hospitals must provide community benefit and charity care to keep their tax exemption, which means financial assistance is often available even when it is not advertised. Ask about it regardless of ownership.
Hospital price transparency rule
A federal requirement, effective 2021, that every hospital publish a machine-readable file of its standard charges and a consumer-friendly display of prices for at least 300 shoppable services.
Why it matters: Compliance is uneven and the files are often hard to use, but the right exists: you can ask a hospital for the price of a planned procedure and it is required to have published one. For anything scheduled in advance, asking is worth the effort.
I
In-network
A hospital or clinician that has a contract with your insurance plan setting agreed prices.
Why it matters: Using an in-network hospital is the single largest factor in what you pay for planned care. Confirm with your insurer rather than with the hospital, and confirm close to the date — contracts end, sometimes mid-year. Note that a hospital being in network does not guarantee every clinician working there is, though the No Surprises Act now limits what that can cost you.
M
Magnet recognition
A credential awarded by the American Nurses Credentialing Center to hospitals meeting its standards for nursing practice and work environment.
Why it matters: It is not a CMS measure and does not appear in federal data, so you will not find it on this site. It signals investment in nursing — staffing levels, autonomy, professional development — which research associates with better outcomes. Treat it as supplementary to the CMS measures, not as a substitute.
Medicare Spending Per Beneficiary MSPB
What Medicare spent on an average patient at this hospital compared with the national average, expressed as a ratio. 1.00 is exactly average; 0.94 is 6% less.
Why it matters: This measures cost to Medicare, not your bill. It will not tell you what you will pay, which depends on your insurance and the prices your plan negotiated. And lower is not automatically better — it can reflect genuine efficiency, or under-treatment. Treat it as context rather than as a quality score.
MRSA Methicillin-Resistant Staphylococcus Aureus
A staph bacterium resistant to several common antibiotics, tracked by CMS when it causes a bloodstream infection acquired in hospital.
Why it matters: Resistance makes it harder to treat, so prevention matters more than usual. Rates reflect hand hygiene, isolation practice and how carefully a hospital screens incoming patients.
N
National benchmark
The national result CMS compares a hospital against, using a confidence interval to decide whether the difference is meaningful.
Why it matters: The three possible verdicts are "better than", "no different than" and "worse than" the benchmark. Most hospitals get "no different" on most measures, and that is a normal result — it means the difference from the national figure is small enough that it could be chance.
No Surprises Act
A federal law effective January 2022 that bars surprise balance billing for emergency care and for out-of-network clinicians at in-network hospitals.
Why it matters: Before this law, you could choose an in-network hospital and still receive a large bill because the anaesthetist or radiologist who treated you was not in your network. Now, for emergency care and most non-emergency care at an in-network facility, you owe only your normal in-network cost sharing. If you get a surprise bill anyway, it may be unlawful — do not simply pay it.
O
Observation status
A classification in which you occupy a hospital bed and receive care but are formally an outpatient rather than an admitted inpatient.
Why it matters: This has real financial consequences that surprise people. Observation care is billed under Part B rather than Part A, so you may face coinsurance on each service and pay out of pocket for routine medications. It also does not count toward the three-day inpatient stay Medicare requires before covering skilled nursing care afterwards. Ask directly whether you have been admitted or are under observation, and ask again if your stay extends.
Overall star rating
A 1-to-5 star summary CMS calculates by combining measures from five categories: mortality, safety of care, readmission, patient experience, and timely and effective care.
Why it matters: It is a starting point, not a verdict. The rating averages performance across many conditions, so a hospital can be excellent at cardiac surgery and average overall. If you know what care you need, the individual measure matters more. And roughly two in five hospitals have no star rating at all, which is usually about low patient volumes rather than poor care.
P
PSI-90 Patient Safety and Adverse Events Composite
A combined score covering pressure ulcers, falls with hip fracture, collapsed lung from medical care, post-operative blood clots, sepsis after surgery and several other avoidable harms.
Why it matters: Because it is a composite, a poor score does not tell you which harm drove it. It is best read as a general signal about safety culture rather than as a specific finding.
R
Readmission rate
The share of patients who returned to any hospital within 30 days of being discharged, risk-adjusted for how sick they were.
Why it matters: It counts returns to any hospital, not just the one that discharged the patient, so a hospital cannot improve its figure by sending returning patients elsewhere. But a high rate can reflect a community with poor access to follow-up care as much as the hospital's own work — risk adjustment accounts for diagnoses, not for poverty, housing or whether anyone is at home to help.
Risk adjustment
A statistical correction that accounts for how sick a hospital's patients were on arrival, so outcomes can be compared between hospitals treating different populations.
Why it matters: Without it, every hospital that takes complex cases would look dangerous and every hospital that treats mild cases would look excellent. With it, the published figure estimates the hospital's own contribution. The correction is good but incomplete: it uses age, sex and documented diagnoses, and cannot see income, housing, language, transport, or social support.
S
Sepsis
A life-threatening response to infection in which the body damages its own tissues and organs.
Why it matters: Sepsis is involved in roughly a third of hospital deaths in the United States, and outcomes depend heavily on how quickly treatment starts. That is why CMS tracks whether hospitals completed every step of the recommended care bundle within three and six hours.
SIR Standardized Infection Ratio
How many infections a hospital actually had, divided by how many would be expected given its patient mix, device use and procedures. 1.00 means as many as expected.
Why it matters: The adjustment is what makes the comparison fair. A large teaching hospital running hundreds of ICU central lines will record more infections in raw numbers than a small community hospital, and comparing counts would punish it for treating sicker patients. Below 1.00 is better than expected; 0.50 means half as many infections as predicted. Hospitals with few eligible cases have results suppressed, which is why small hospitals often show nothing here.
T
Teaching hospital
A hospital that trains resident physicians, usually affiliated with a medical school.
Why it matters: Teaching hospitals tend to handle the most complex cases and offer treatments community hospitals cannot, which is why they matter for rare conditions and complicated surgery. The trade-off is that you may be seen by residents under supervision, and large academic centres often score lower on patient experience measures like quietness at night.
The Joint Commission
The largest of several independent organizations that accredit U.S. hospitals. CMS recognises its accreditation as evidence a hospital meets federal participation requirements.
Why it matters: Accreditation is a floor, not a distinction — almost every hospital you would consider has it. Its absence is worth asking about; its presence tells you little.
Trauma center level
A designation from Level I to Level V describing how much trauma capability a hospital has. Level I has full surgical specialty coverage available at all times; Level V provides initial evaluation and transfer.
Why it matters: For severe injury this matters more than any star rating. A Level I or II centre can get a trauma surgeon into an operating room immediately, which is the thing that determines outcomes after a serious crash or fall. Emergency services route major trauma to these centres for this reason — which is also why you should call 911 rather than drive yourself.