W. Edwards Deming and the Funnel Experiment

There is assorted information regarding Dr. Deming’s Funnel Experiment.  This Experiment was conducted during Dr. Deming’s famous 4-day seminar – I attended my first Deming seminar back in the 1980’s at the invitation of Allison Transmission as a supplier.  As with many folks, this had a profound impact on my thinking about management.

During Dr. Deming’s 4-day seminar we broke out into groups supported by consultants (most statisticians) to facilitate our learning regarding the concepts taught us.  The purpose of this exercise was to teach us what happens when management tampers with systems without knowledge.  Tampering is a really good word as it represents what most managers do when they manage from assumption and data that carries no context.

The funnel experiment itself has been a source of confusion as to how it is conducted, this is not as important as what needs to be learned from tampering with systems without knowledge.  I will describe how each of the four Rules of the Funnel Experiment and examples of associated tampering with that Rule.

Most important, is that the Funnel Experiment describes variation.  Tampering is to treat a common cause of variation as a special cause and vice versa.  Without a fundamental understanding of variation, you stand to make mistakes or “tamper.”  If you are not familiar with the concepts of variation, I wrote a post titled, Service Metrics:  What You Need to Understand.

Let’s start with the four (4) Rules of the Funnel Experiment:

  1. Make no Adjustment to the Funnel – Just keep it centered on the target.
  2. Adjust the Funnel from Its Last Position – Start with the Funnel on the target.  If the marble falls 3 inches North of the target the next drop will be 3 inches South.  The second drop starts from 3 inches South as the new target and if the next drop lands 5 inches East of this (new) target then the next drop is conducted 5 inches West of the (3-inches South) target.
  3. Bring Back to Original Target Before Adjustment – Start out at a static target.  If the drop is 5 inches North of the target, then the next drop (new target) will be 5 inches south – this is the same as Rule 2.  If the next drop lands another 2 inches south then you are now a total of 7 inches South from the original “static” target.  Now the next drop will be conducted 7 inches North of the “static” target.
  4. Set the Funnel at Each Drop Over the Spot Where It Last Came to Rest – Pretty simple.  Just start with your target and then where the marble drops becomes the new target.

Rule 1 is always the best option.  This does not mean that targets are good for business, but having a customer purpose (aim in Deming terms) is important.  There will always be variation (different spots the marbles come to rest) in the system.  Manipulating the system is where the tampering begins.

Rules 2, 3 and 4 are all methods that result in increased variation or tampering.  I have pulled examples of tampering from W. Edwards Deming’s Out of the Crisis and The New Economics, Kenneth T. Delavigne’s Profound Changes and William Latzko’s Four Days with Dr. Deming as well as my own experiences.

Rule 2 (results in 41% more variation):

  • Legislation, Federal and State, tampering with our economy – We have witnessed far too much of this!
  • Adjustments by the Federal Reserve Board – Ron Paul has a point!
  • Overreaction to a complaint by a customer – Two actions you should take one is to see if the problem is systemic or not (repeated) and two – take an administrative action to fix the customer.
  • Reaction of stock market to news.
  • Changing company policy based on latest attitude survey.
  • Continual changes in tax laws and health benefits, each change to correct a previous mistake.
  • Price wars that end in competing companies having no investment capital to innovate and improve.
  • Over ordering supplies in one month and under ordering supplies the next month.
  • Adjusting a rifle’s sight after each shot.
  • Taking immediate action on defects, errors or violations.

Rule 3:

  • Escalation of bets in a “hot” poker hand.
  • Short-term “contracyclical” manipulation of credit, money supply and public works expenditures by the government trying to cancel out the “business cycle” but actual causing it to occur.
  • Escalation of barriers to trade between nations.
  • Sending children to bed early tonight because they stayed up late last night.
  • Trying to exceed customer expectations this month to make up for bad service last month.
  • Pulling in orders from next month to compensate for cancellations this month.
  • Nuclear proliferation.
  • Illicit drug crackdowns.  Enforcement improves, price goes up which stimulates importation of drugs.

Rule 4 (Off to the Milky Way):

  • Marking the next board to cut by using the board previously cut.
  • Making copies of copies where the original is constantly replaced by a copy.
  • One employee being trained by an incumbent employee.
  • Taking a sample from the last batch (as with paint) to be used as measurement standard for the next batch.
  • Languages.
  • History, unwritten passed down from generation to generation.
  • Get together and share ideas.
  • Executives meeting to discuss what to do in this new economic age.
  • Adjustment of time to a meeting based on the last actual starting time.
  • Playing “telephone.”

As stated, Rule 1 is the best choice and Rule 4 is the worst choice, but Rule 2 & 3 are sub-optimal compared to Rule 1.  Tampering is evident in every system and many organizations can not recognize when they are tampering.  This is when outside help is needed to understand when things are being made worse by the actions taken.

Tripp Babbitt is a speaker, blogger and consultant to service industry (private and public).  His organization helps executives find a better way to make the work work.  Read his articles at Quality Digest and his column for CustomermanagementIQ.com.  Learn more about the The 95 Method for service organizations.  Reach him on Twitter at www.twitter.com/TriBabbittor LinkedIn at www.linkedin.com/in/trippbabbitt.

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