Week 7 Workshop 4: Control Charts

The tools practiced in this workshop are:

• Individuals (X) Control Chart

Situation:

An outpatient medical clinic has determined that there is a problem with their patient flow process. The time from patient check-in until they leave the clinic has been inconsistent. This has led to increasing patient dissatisfaction, decrease in patient referrals, and decrease in revenue.

At the beginning of their "Patient Cycle Time Reduction" Six Sigma project, the team collected baseline measurements of their patient flow cycle time from their clinic database.

The data collected consisted of the number of minutes from check-in to departure. The average cycle time for each day was calculated for 30 consecutive days.

Instructions:

Use the data from the Workshop 4 Data Excel Spreadsheet located in the Workshop 4 Drop-box instructions to assist you with the activities that follow.

Activities:

1. Calculate:

1. Mean:
2. Standard Deviation

2. Calculate:

1. Upper Control Limit:
2. Lower Control Limit:

3. Manually generate a X (Individual) Control Chart with Microsoft Excel and paste it in the space below. DO NOT use additional statistical software packages.

4. Based on the Control Chart, do you see any Special Causes of Variation? If so, what are they?

A B C Day Wait Time 2 Day 1 81 3 Day 2 82 4 Day 3 84 5 Day 4 77 6 Day 5 107 7 Day 6 92 8 Day 7 71 Day 8 87 Day 9 73 11 Day 10 81 12 Day 11 70 13 Day 12 78 Day 13 64 15 Day 14 78 Day 15 76 17 Day 16 72 18 Day 17 71 19 Day 18 66 Day 19 64 Day 20 74 22 Day 21 75 Day 22 74 Day 23 64 25 Day 24 72 26 Day 25 69 27 Day 26 67 28 Day 27 62 29 Day 28 70 30 Day 29 60 31 Day 30 72 32