Quality management through statistics.
One of the responsibilities of a quality assurance professional is to assess patient care data in an effort to meet "outcome" requirements as established by the institution, the patient, the patient's family, the Joint Commission, the Health Care Financing Administration, the state PRO, and other regulatory agencies. A major goal of effective quality management is to assure that patients treated in a similar diagnostic category achieve similar outcomes. To accomplish this, the QA manager must gain and maintain control over patient care processes. To obtain this control, the conditions of patient care processes must be measured. Over one hundred years ago, the English scientist Lord Kelvin said, "When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in numbers, your knowledge is...unsatisfactory." This article will describe some of the statistical quality control techniques that will assist in measuring the performance of specific patient care processes and outcomes and expressing them in numbers. A review of the numbers will show whether a particular patient care process is running smoothly or needs further investigation or adjustments. Using statistical quality control techniques will enable the QA manager to predict how well patient care processes and outcomes will run in the future. The simple statistical techniques discussed in this article can be used to measure the performance of patient care processes and outcomes both before and after corrective actions have been taken. They apply both to attempts to bring a specific process or outcome into "control" or to break through to a new, improved level of quality performance.