Facebook Twitter Instagram You Tube Pinterest LinkedIn RSS Podcasts Video Library Blog
 - Northwestern Memorial Hospital - Chicago

How We Measure Quality

At Northwestern Memorial, we describe quality simply as Delivering Exceptional Care - care that is effective, timely, safe, courteous and convenient. Hospitals measure quality in two ways:

Treatments and procedures

This type of quality measure is used to assess whether hospitals are using the right treatments and procedures when patients are in the hospital. We choose measures that are valid and reliable and focus on those that can be compared with data from government and other national organizations.

An example of a treatment and procedure measure is:

  • The percentage of patients suffering a heart attack who were given an aspirin when they arrived at the hospital

    The National Centers for Medicare and Medicaid Services collect data on this measure because studies have shown that a patient who takes an aspirin while suffering a heart attack has a greater chance of survival.


This type of measure assesses the success of the treatments and procedures patients receive in the hospital. However, outcomes are very difficult to measure and statistically analyze successfully and equally because every patient is different.

For example, an otherwise healthy 23-year-old patient who has pneumonia will not have the same chance of survival as a 93-year-old patient with underlying heart disease or other conditions. Because of these sometimes vast differences, there are not many valid and reliable outcome measures available.

A few leading independent national measurement agencies have developed statistical methods to adjust for severity of patient illness when predicting outcomes, such as risk of mortality and complications. These models aren’t perfect and should not be the sole deciding factor when choosing a healthcare provider or hospital, but we have included relevant outcome measures adopted by these leading agencies in our Quality Rating.

Examples of outcome measures are:

  • How many patients who arrive at the hospital with a heart attack survive to discharge?

    This is measured by the federal Centers for Medicare and Medicaid Services. Heart attacks are a common cause of death, but when heart attack patients quickly receive the right care, their chance of survival increases. Treatments and procedures at a hospital can have an effect on heart attack survival, so this measure may be an indicator of the quality of care a hospital provides.
  • How many patients develop an infection after surgery?

    This is measured by the American College of Surgeons’ National Surgical Quality Improvement Program. Surgical infections can cause pain, and in some cases, they cause significant harm to patients. Because most surgical infections are preventable, post-surgical infection rates are important quality measures.
Last UpdateDecember 27, 2011

Questions & Comments

If you have a question or comment about our Quality Ratings, please complete our online questions & comments form and we will respond within two business days. If your concern requires immediate attention, please call 312-926-3112 so that a Patient Representative can assist you.