Quality in healthcare refers to how well health services achieve the outcomes people want while staying consistent with current medical evidence. It’s not a single metric but a framework of goals: care should be safe, effective, timely, efficient, equitable, and centered on what patients actually need. These six aims, originally defined by the Institute of Medicine, remain the foundation that hospitals, insurers, and government agencies use to measure and improve care in the United States and globally.
The Six Aims That Define Quality
The Institute of Medicine laid out six domains that together capture what quality care looks like. They’ve shaped nearly every measurement system, accreditation standard, and improvement program in use today.
Safe means avoiding harm from the care itself. This includes preventing medication errors, surgical complications, and hospital-acquired infections. Effective means delivering treatments backed by scientific evidence to people who will benefit, while not providing services to those who won’t. Both underuse (skipping a proven treatment) and misuse (applying the wrong one) count as failures of effectiveness.
Patient-centered care is respectful of and responsive to individual preferences, needs, and values. The goal is that patient values guide clinical decisions, not just clinical protocols. Timely care reduces waits and harmful delays for both patients and providers. Efficient care avoids waste of equipment, supplies, ideas, and energy. Equitable care does not vary in quality based on personal characteristics like geographic location or socioeconomic status.
The World Health Organization uses a similar but slightly broader list, adding “integrated” to the mix, meaning care should be coordinated across providers, settings, and time rather than fragmented into disconnected encounters.
How Quality Gets Measured
A physician and researcher named Avedis Donabedian created the classification system most widely used to organize quality measures into three categories: structure, process, and outcome.
Structural measures look at the capacity and systems a healthcare organization has in place. Examples include whether a hospital uses electronic medical records, the proportion of board-certified physicians on staff, and the ratio of providers to patients. These don’t tell you directly how well patients do, but they indicate whether the foundation for good care exists.
Process measures track what providers actually do. What percentage of eligible patients received mammograms or immunizations? How many people with diabetes had their blood sugar tested and controlled? These reflect whether recommended clinical practices are being followed and make up the majority of quality measures used in public reporting. If you’ve ever seen a hospital comparison website showing percentages of patients who received a specific treatment, those are process measures.
Outcome measures capture the results: surgical mortality rates, rates of hospital-acquired infections, complication rates. Outcomes might seem like the gold standard, but they’re influenced by many factors beyond a provider’s control, including how sick the patient population is to begin with. Statistical models that adjust for patient health status help make these comparisons fairer, though no adjustment is perfect.
Star Ratings and Public Reporting
The Centers for Medicare and Medicaid Services (CMS) distills hospital performance into a one-to-five star rating calculated from 45 individual quality measures. These measures fall into five groups, each carrying a specific weight: mortality (22%), safety of care (22%), readmission (22%), patient experience (22%), and timely and effective care (12%). If a hospital doesn’t have data for a particular group, its weight gets redistributed across the remaining categories.
The metrics within these groups range from death rates for specific conditions to infection rates, how quickly emergency departments move patients through, and how patients rate their communication with nurses and doctors. These star ratings are publicly available and designed to help people compare hospitals before choosing where to receive care.
What Patients Are Asked About
Patient experience is measured through a standardized survey known as HCAHPS, administered to adults after a hospital stay. As of January 2025, the survey produces 11 measures covering communication with nurses, communication with doctors, responsiveness of staff, how well medicines were explained, care coordination, the restfulness of the hospital environment, discharge information, cleanliness, quietness, and two overall ratings of the hospital.
Several of these are composite measures, meaning they combine multiple survey questions that are statistically related. For example, “communication with doctors” isn’t based on a single yes-or-no question but on several questions about whether doctors listened carefully, explained things clearly, and treated the patient with respect. These surveys directly influence hospital star ratings and, in turn, hospital reimbursement. Poor patient experience scores cost hospitals money, which gives them a financial incentive to improve.
The Cost of Getting It Wrong
Poor quality care carries enormous financial consequences. Around 15% of hospital expenditure in high-income countries results from mistakes in care or patients acquiring infections while hospitalized. The broader economic toll, including long-term disability, lost productivity, and impairment from preventable harm, runs into trillions of dollars globally each year.
These costs aren’t abstract. They show up as longer hospital stays when a patient develops a preventable infection, repeated surgeries when the first one goes wrong, and chronic health problems that could have been avoided with timely, evidence-based treatment. For individual patients, low-quality care means unnecessary suffering. For health systems, it means resources spent treating problems that shouldn’t have occurred in the first place.
Equity as a Quality Issue
Healthcare quality increasingly includes how well systems serve different populations. If outcomes for a given condition differ significantly based on a patient’s race, income, zip code, or language, that gap is treated as a quality problem, not just a social one. The National Committee for Quality Assurance (NCQA) has been building health equity into its accreditation standards, with programs being restructured in 2026 to focus on measurable health outcomes across populations and community-focused care strategies.
This shift reflects a growing recognition that average quality scores can mask wide disparities. A hospital might perform well overall on diabetes management metrics while consistently underserving patients in certain neighborhoods or demographic groups. Measuring equity separately forces organizations to look at who benefits from quality improvements and who gets left behind.
What This Means in Practice
If you’re trying to evaluate the quality of a hospital or health system, the frameworks above are what power the tools available to you. CMS star ratings on Medicare’s Hospital Compare website, state health department report cards, and insurer quality rankings all draw from the same categories: Are patients safe? Are proven treatments being delivered? Are patients satisfied? Are outcomes improving?
No single number captures quality perfectly. A hospital might excel at surgical outcomes but score poorly on patient communication, or perform well on process measures while struggling with readmission rates. The most useful approach is to look at the dimensions most relevant to your situation. If you’re facing surgery, mortality and complication rates matter most. If you’re managing a chronic condition, process measures around evidence-based treatment and care coordination are more telling. Quality in healthcare isn’t one thing. It’s a set of goals that, taken together, describe what good care looks like from every angle.