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Funnel Experiment SimulatorDeming's Funnel Experiment Simulator

The funnel experiment is a famous illustration by Dr. W. Edwards Deming to show the adverse effects of adjusting a process when not required.

A process not subject to any external causes of variation also shows some random variation. If you adjust the process in response to such random variation, you would be overadjusting the process. Overadjustment actually induces more variation in the process than would occur if a random cause process is left alone.

These principles are illustrated by simulating adjustments in a random cause process of dropping beads through a funnel. Various methods of process adjustments are simulated through four rules. The rules adjust the process in different ways and let you observe the outcome.

Dr. W. Edwards Deming
Dr. W. Edwards Deming
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The Simulator:

The funnel experiment simulator enables you perform the experiment on your computer. The visually appealing graphics give you the same clarity as performing the experiment with a real funnel.

The simulator does away with the problems associated with the mechanical apparatus. You do not have to keep levelling the table, neither do you have to actually measure and plot the data.

The simulator mimics the real variation that occurs due to randomness of the process as well as the one caused by systematically adjusting the funnel. Plotting of scatter maps and run charts for each adjustment rule is automatic. You can visually compare the scatter maps for various adjustment rules.

The funnel experiment session goes at a brisk pace. The visual appeal is maintained intact for an easy understanding.

Comparison plots for the four rules

Rule 1 gives lower variation than Rule 2; Rule 3 tends to blow up; and Rule 4 results in a "random walk".

Explanation of the four rules:
  • On clicking the "Explain" button, the simulator displays a lucid explanation of how the four rules work.

  • Use "Runs Summary" to compare up to eight previous simulation results.

  • The simulator includes an option to raise and lower the funnel in order to change the "inherent" variation in the process.

  • The simulator also plots a run chart showing the deviation from target at each drop of the marble.

Check out this excellent article on
Dr. Deming's Funnel Simulator

Rule 1Rule 2
Funnel Experiment: Rule 1 Funnel Experiment: Rule 2
Rule 3Rule 4: Random Walk
Funnel Experiment: Rule 3 Funnel Experiment: Rule 4- Random Walk

Heads Up !

Adobe has ended support to Flash.

The Deming's Funnel Experiment Simulator uses Adobe Flash Player for animations.

As you may be aware, Adobe has recently announced end of support for Flash. Consequenlty, all browsers have also stopped supporting Flash content. As a result, any software or Flash-based animations have stopped working. The online, browser-based versions of these programs have also stopped working.

Deming's Funnel Experiment Simulator is being temporarily withdrawn.

We sincerely regret the inconvenience this will cause you. We want to ensure that you continue to use the simulators. We have already begun re-programming these software to run without using Flash animations.

Watch this space !

What our users say...

Kevin Mader: I liked the Funnel Experiment and it had me looking up the distributions in OOTC. It was spot on. I also liked that you gave the user the option to raise and lower the funnel. Having an explanation of the Rules was also very good.

Tom Kochuyt: Very useful to illustrate the concept of tampering.

Christopher Cleveland: Sure beats my explanation to Yellow belts..... Gets the point across and saves time.

Jack Meagher: This is the best representation of the funnel experiment I have seen when you have the "Explain" option which visually shows what the rules mean.

Keith Taylor: Very clear explanation of rules for the funnel experiment.

Robert Samagalsky: Your Funnel simulation is most ingenious and well done.

Explanation of how the funnel rules work.
Other Training Aids
From SymphonyTech:
Deming's Red Bead Experiment Simulator Deming's Red Bead Experiment Simulator
SPC Training Simulator (Quincunx Simulator)
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