Red Bead Roulette.

Have you ever been to a casino? My parent took me a few times when I was younger. I avoided the card games as they seemed to require skills that I knew I did not have. I favoured roulette. That big wheel with numbers around the edge. The brief flash of the ball as it left the skilled croupier’s (?) hand, and the tick, tock, plunk as the ball decided the fate of the anxious gamblers and the fresh faced maths geek.

Now imagine a variant on the game. You get to run the game twenty times. Each time, you have to bet on black. You count up the number of times you win. This is your score.

Now run the game again. But this time make a change. Instead of one person placing the bet, get two, or five, or one hundred. Will it change the results?

Now try doing it standing on one leg.

Or with a glass in your hand. A glass containing whiskey. Now drink the whiskey. Drink lots of whiskey. Drink whiskey with ice, and whiskey without ice.

Do any of these changes make any difference to the score?


The outcome of the game is determined by the inherent randomness of the process and the constraints placed on it (always bet on black).

This is Deming’s famous red bead experiment. It is meant to teach us that nothing we do will affect the outcome of the system. It proves that the system dominates. It ensures that by construction.

Consider an game that is more a production process in the real world. Imagine a casino where we could do whatever we like. the individuals playing the game might decide the take the ice cubes out of their whiskey glasses (there are a hundred playing so numbers count. whiskey with ice is needed) and block the red and white slots in the wheel. This would force the ball to always land on black.

That’s what inidividuals do. They change the rules of the game. They change the system.

Next time someone offers to play the red bead game, discreetly remove all the “bad” beads before one of the goes. That way, you can demonstrate to the people running the game that the system does not dominate and that individuals can have an affect bigger than 6%. Of course, expect them to be angry because they are the ones in control of the system.

I would like to thank Don Reinertson for inspiring me to think about the “Red Bead Con” with his keynote at Lean Kanban Benelux

About theitriskmanager

Currently an “engineering performance coach” because “transformation” and “Agile” are now toxic. In the past, “Transformation lead”, “Agile Coach”, “Programme Manager”, “Project Manager”, “Business Analyst”, and “Developer”. Did some stuff with the Agile Community. Put the “Given” into “Given-When-Then”. Discovered “Real Options” View all posts by theitriskmanager

3 responses to “Red Bead Roulette.

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