1. Causal Control Chart
Farrokh Alemi, Ph.D.

2. Weigh data so alternative explanations occur as often prior as after the intervention
Remove Confounding

3. Method Based On:

4. Data Based On:

5. Goal: Same Rate of Backups Because of Alternative Explanations
Month
Pre-Intervention Controls 1 2 3 4 5 6 7 8 9 10 11 12 13
Total Examined
No Backup 17 27 21 15 18 29
Image Backup 16 26 24
Bed Availability
Both Backup 14
Post-Intervention Cases 19 20 22 23 25 35

6. Step 1: Calculate Average of Controls
Month
Pre-Intervention Controls 1 2 3 4 5 6 7 8 9 10 11 12 13
Average
Total Examined
No Backup 17 27 21 15 18 29
12.69
Image Backup 16 26 24
17.08
Bed Availability
5.00
Both Backup 14
12.92

7. Step 2: Calculate Weights
Alternative
Explanations
Post-Intervention Cases
Average Controls 14 15 16 17 18 19 20 21 22 23 24 25
Total Examined
No Backup 10 9 29 6 2 26 27 12
12.69
Image Backup 4 5 8 13
17.08
Bed Backup 35
5.00
Image & Bed Backup
12.92
Weights
0.79
0.71
1.81
2.28
1.89
0.47
1.97
0.16
2.05
2.13
0.95
0.23
0.29
0.76
0.00
0.35
1.35
1.05
0.88
1.11
0.82
0.12
1.20
3.00
0.40
3.40
2.60
4.20
1.80
4.80
7.00
0.70
1.93
0.77
1.32
1.39
1.70
2.09
1.47
1.24
1.16
Cases
Control

8. Post-Intervention Cases Total Weighted Controls
Step 3: Weigh Controls
Month
Post-Intervention Cases
Average Controls 14 15 16 17 18 19 20 21 22 23 24 25
Total Examined
No Backup 10 9 29 6 2 26 27 12
12.69
Image Backup 4 5 8 13
17.08
Bed Backup 35
5.00
Both Backup
12.92
Weights
0.79
0.71
1.81
2.28
1.89
0.47
1.97
0.16
2.05
2.13
0.95
0.23
0.29
0.76
0.00
0.35
1.35
1.05
0.88
1.11
0.82
0.12
1.20
3.00
0.40
3.40
2.60
4.20
1.80
4.80
7.00
0.70
1.93
0.77
1.32
1.39
1.70
2.09
1.47
1.24
1.16
Total Weighted Controls 54 43 44 61 72 62 68 81 92
By design same as total of cases
Total Weighted Control = SUMPRODUCT(Range of Avg Control, Range of weights)

9. Step 4: Weigh Excessive Boarding
Month
Post-Intervention Cases
Average Controls 14 15 16 17 18 19 20 21 22 23 24 25
Total Examined
No Backup 10 9 29 6 2 26 27 12
12.69
Image Backup 4 5 8 13
17.08
Bed Backup 35
5.00
Both Backup
12.92
Weights
0.79
0.71
1.81
2.28
1.89
0.47
1.97
0.16
2.05
2.13
0.95
0.23
0.29
0.76
0.00
0.35
1.35
1.05
0.88
1.11
0.82
0.12
1.20
3.00
0.40
3.40
2.60
4.20
1.80
4.80
7.00
0.70
1.93
0.77
1.32
1.39
1.70
2.09
1.47
1.24
1.16
Weighted Controls
Total 54 43 44 61 72 62 68 81 92
57.83
Excessive Boarding 31 28 45 41 47
31.42
Probability
0.52
0.65
0.42
0.41
0.61
0.51
0.60
0.45
0.66
0.57
0.54
Wt UCL
0.81
0.74
0.73
0.72
0.69
Wt LCL
0.26
0.33
0.31
0.34
0.36
0.37
0.38
Weighted Excessive Boarding = SUMPRODUCT (Range of Excessive Boarding
in Avg Controls, Range of weights)

10. Step 5: Weighted Control Limits
Month
Post-Intervention Cases
Average Controls 14 15 16 17 18 19 20 21 22 23 24 25
Total Examined
No Backup 10 9 29 6 2 26 27 12
12.69
Image Backup 4 5 8 13
17.08
Bed Backup 35
5.00
Both Backup
12.92
Weights
0.79
0.71
1.81
2.28
1.89
0.47
1.97
0.16
2.05
2.13
0.95
0.23
0.29
0.76
0.00
0.35
1.35
1.05
0.88
1.11
0.82
0.12
1.20
3.00
0.40
3.40
2.60
4.20
1.80
4.80
7.00
0.70
1.93
0.77
1.32
1.39
1.70
2.09
1.47
1.24
1.16
Weighted Controls
Total 54 43 44 61 72 62 68 81 92
57.83
Excessive Boarding 31 28 45 41 47
31.42
Probability
0.52
0.65
0.42
0.41
0.61
0.51
0.60
0.45
0.66
0.57
0.54
Wt UCL
0.81
0.74
0.73
0.72
0.69
Wt LCL
0.26
0.33
0.31
0.34
0.36
0.37
0.38

11. Step 6: Plot Chart

12. Limits are based on same rate of image and bed backup
Step 6: Plot Chart
Limits are based on same rate of image and bed backup

13. Step 7: Interpret Chart
Holding alternative causes of backup constant, new hire reduced excessive boarding