A hospital is interested in improving its processes as it is losing money on bowel surgery patients reimbursed through Medicare. A stratification approach was employed to achieve "risk adjustment" and the quality improveme nt team analyzed data on patients undergoing elective surgery, who were 65 years of age or older, and were having a single procedure. The selected measure is the post-operative length of stay (LOS). The table below shows LOS for a randomly selected patient each month for 30 months. A new pathway was introduced after the 18th month.
|
Month
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
11
|
12
|
13
|
14
|
15
|
|
LOS
|
8
|
11
|
12
|
9
|
11
|
6
|
19
|
7
|
9
|
13
|
8
|
9
|
14
|
8
|
15
|
|
Month
|
16
|
17
|
18
|
19
|
20
|
21
|
22
|
23
|
24
|
25
|
26
|
27
|
28
|
29
|
30
|
|
LOS
|
6
|
7
|
11
|
6
|
7
|
6
|
8
|
8
|
7
|
6
|
9
|
8
|
7
|
9
|
9
|
a. Construct appropriate control charts for before and after introduction of the new pathway. Discuss process stability and the results.
b. Can you conclude that the new pathway has caused a significant reduction in the average length of stay? Test using α = 0.05.