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Dec. 2014 Meeting Summary - Deming Red Bead Experiment

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Category: Newsletter
Published Date Written by Robin Francis, Ph.D.

Deming Red Bead Experiment

by Robin Francis Ph.D.,P.Eng.

Red_Bead_PresentationDuring the ASQ London section meeting on Dec 11, 2014 at the London North Optimist Community Centre Keith and Mark did a demonstration of Dr. Deming’s red bead experiment. The purpose of the experiment was to demonstrate the fallacy of rating people and ranking them in order of performance for next year, based on previous performance. 

The Red Bead Experiment uses statistical theory to show that even though a “willing worker” wants to do a good job, their success is directly tied to and limited by the nature of the system they are working within. Real and sustainable improvement on the part of the willing worker is achieved only when management is able to improve the system.
Red_Bead_Inspector_TableThe exercise used a population of 4000 beads (3500 green beads and 500 orange beads). 4 workers sampled from the population 50 beads at a time with replacement. The number of orange beads obtained for each worker was recorded. The goal is to have 6 or less orange beads (analogous to defective product) in a sample of 50. The results obtained by from the experiment are shown in the table below:

The exercise clearly demonstrated the futility of setting hypothetical goals without understanding the capability of the production process. It also demonstrates the vainness of rewarding or disciplining “willing workers” before understanding the capability of the process.

Further information on Deming’s Red Bead Experiment can found on-line.