Question

The time taken to discharge a patient in a hospital depends on many factors such as insurance clearance, clearing bills not cover under insurance etc. A hospital sets a target that the time to discharge a patient should be less than 120 minutes. Any discharge taking more than 120 minutes is unacceptable. Analysis of previous data shown that the average time to discharge a patient is 150 minutes with a standard deviation of 20 minutes (assume normal distribution). Calculate the Sigma Score of the discharge process. If the calculated Sigma Score is negative, explain under what conditions the process will have negative Sigma Score?

Answer 1

Z score/Sigma score = data point - mean/ standard deviation

= 120-150/20 =-1.5 minutes

In the case of task times, a negative process sigma is ideal–as you want more people completing the task below the task time, not above it. You can simply drop the negative when communicating the results in the event it causes confusion.

Hence it means that the hospital is now working with a discharge time below 120 minutes