The Red Bead Experiment

W. Edwards Deming. 1986. Out of The Crisis: 346-354
W. Edwards Deming. 1994. The New Economics: 154-171

Yonatan Reshef
School of Business
University of Alberta
Edmonton, Alberta
T6G 2R6 CANADA

Employee

Day 1

Day 2

Day 3

Day 4

TOTALS

 

 

         
 

 

         
 

 

         
 

 

         
 

 

         
 

 

         
Daily Total        

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Daily Average        

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GrandTotal

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GrandMean

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GrandTotal/24

Class Activities

1. Plot the results on a control chart.

Calculating the control chart's parameters

  1. The central line on the chart is placed at the average count (GrandMean).
  2. Calculate Sigma:

Note, 50 is the number of depressions in the paddle (the daily production of each employee).

    GrandTotal = SUM {DailyTotal}

    GrandMean = GrandTotal/24

     

  1. Calculate the Upper and Lower Control Limits:
  2. Plot the results (the daily production, the line of grand mean, and the UCL and LCL).

2. How predictable are the four daily averages (DailyTotal/6)?
3. What is the relationship between the four daily averages and the ratio of the red/white beads?  Why?
4. What are the characteristics of the production system in the experiment?
5.
What are the (dis)advantages of such a system?
6.
How can one improve this system?
7.
The inspectors -- divided responsibility and the hazard of consensus
8.
Provide real-life examples.