The sun was hot on my face as I tried to keep my laptop in the shade of the umbrella outside my favorite coffee shop.

From my left, I was startled by the sound of a young rascal coming out the door with the dreaded straw-in-a-juice-box combination, apparently locked and loaded.  Trailing close behind was his mother talking on the phone and carrying a mammoth cup filled with the latest barista-terrifying concoction.

The youngster ran to an open table, pulled the chair out, and, as he jumped up on the chair, heedlessly squeezed the juice box, splattering himself and the table in a stream of sticky juice.

“Be careful,” his mother admonished.  “Don’t squeeze the box!”

He was oblivious to this caution and, as his weight settled onto the chair, he looked intently at the juice box and gave it another squeeze.

This only set the young woman in a fervor.  A muffled yell, “Why did you do that?” pulled him out of his stupor.  “I just told you not to squeeze the box!”

The look on his face shifted from the inquisitive gaze at the juice box, to a look of confusion toward his mom as she proceeded to wipe his face with a napkin from the nearest dispenser.

As an innocent bystander, I chuckled to myself as I realized he was unknowingly toying with Deming’s Theory of Knowledge.


As a long time student of the work of W. Edwards Deming, I surmised that he was developing a theory of the squirting juice box.

In Deming’s writing on his Theory of Profound Knowledge in The New Economics (1994), he states, “Knowledge is built on theory.”  Deming’s writing on this topic was a confusing read for me until I realized he uses the words “theory” and “knowledge” in two different ways.

Using “Theory” as used in “Theory of Knowledge,” he stated that we learn more when we make a prediction and perform an experiment.  And using “knowledge”, he is talking about how we know and learn. Why did the boy squeeze the juice box again?

He also used “theory” to refer to the system, question or theory we have in mind.

Why does the juice box squirt when squeezed?

            What is the theory or mechanism that translates the squeeze into a squirt?

The “knowledge” in this case is what we know, our understanding as a “theory” that can be used to predict.


I’ll call these big Theory of Knowledge (capitalized), and little theory, our understanding of the system with which we are working.

In the last decade of doing process improvement work with the tools of Lean Healthcare, I have found that many people not only don’t understand their work as a system, but have never even looked at areas beyond their daily work.  A new triage nurse knows their work well, but has never gone to another interfacing department (i.e. diagnostic departments: lab, radiology, etc.) to understand the system in which they play a role.

Deming also wrote about “appreciation of a system” and the need for leaders and workers to understand that they are not just a collection of independent units, but an integrated whole built of separate, but interrelated, components.  Lean Healthcare leaders must have a theory, or understanding of the system, with which they can predict.  To validate and grow this theory of the system, they must plan experiments with predicted outcomes, run tests and check the results.  This generates new knowledge.


For example, in one hospital we developed a model using historical data from the Environmental Services dispatch system to predict the average number of dirty beds at 5pm on weekdays.  By validating that our prediction was accurate, we were able to adjust staffing hours to align with with the cleaning demand during the day to reduce the backlog of dirty beds every afternoon.

In another hospital, by delving into the low acuity patient flow process, we were able to develop a theory to predict the in-room length-of-stay (LOS).  As we experimented with process changes, we could validate our theory and understanding of this new model of patient flow.  Then we could make permanent process changes to move in the direction of shorter LOS and higher throughput with the available rooms.    (Comment below if you would like to hear more about either of these.) 

So, what does this have to do with the boy and his juice box?

Observing the situation at hand, I believe that the first squeeze and subsequent squirt was just an accident.  As he tensed for the jump, he squeezed the box.

Reading the puzzled look on his face as he pondered what had just happened, I could sense a question forming.  “Does the squeeze cause the squirt?”

The second squeeze was really a cause and effect experiment to see if it would do it again.  And, sure enough, it did.  His mother’s rebuke shook him from his focus.  “Why did you make such a mess?” she asked stifling his curiosity.

His eyes met mine with a knowing look, “You understand, don’t you?”  However, tempted as I was, I did not offer to buy him another box of juice to perform more experiments, but packed my laptop and headed to the airport.


Richard Tucker, Vice President for Lean Healthcare and Process Improvement Training at HPPToday’s blog was written by Richard Tucker, senior consulting director with HPP.

Richard serves as a coach, facilitator, and project manager for healthcare clients in the training and implementation of Lean Healthcare tools and Lean management systems. Prior to joining HPP, Richard had more than 16 years of business and industry experience in operational and leadership positions.  In addition to his ongoing support of healthcare organizations in their lean journey, Richard is a founding faculty member of Belmont University’s Lean Healthcare Certificate Program.

Richard’s educational background includes BS and MS degrees from Tennessee Technological University in Cookeville, Tennessee. Richard has attended formal training courses in Lean Manufacturing, Leadership Development, and Shainin Statistical Problem Solving.

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