Canadian Health Information Management Association Practice Exam

What does an average length of stay (LOS) of 3.7 days with a standard deviation of 20 indicate about patient stay variations?

1. Most patients had a LOS of 3-4 days.

2. Patients stay longer than average.

3. There is a large variation in the LOS.

4. There is a small variation in the LOS.

The correct answer is: There is a large variation in the LOS.

An average length of stay (LOS) of 3.7 days coupled with a standard deviation of 20 indicates a significant amount of variability in the patient stay durations. The average provides a central point around which data is clustered, while the standard deviation measures how much individual data points typically differ from that average. In this case, a standard deviation of 20 suggests that many patients' lengths of stay deviate quite substantially from the average. Since the standard deviation exceeds the average itself, it implies that patient stays can vary widely, with some patients potentially experiencing stays that are much shorter or much longer than the average of 3.7 days. This is indicative of a wide range in lengths of stay and supports the idea of considerable variability among patients. The other choices do not accurately reflect the implications of the standard deviation measurement. The average LOS of 3.7 days alone does not justify the assertion of most patients staying within a narrow range around that average, nor does it indicate that patients generally stay longer or shorter consistently. The large standard deviation is what primarily communicates the variability among patient stay durations.