A Great Poster in a Lean Hospital Lab – Asking Why


As a student of Dr. W. Edwards Deming's books and teachings, I'm not a big fan of slogans and posters in the workplace.

Last week, visting a hospital laboratory to do research for my upcoming book  Healthcare Kaizen: Engaging Front-Line Staff in Sustainable Improvements, I saw the following poster hanging over a metrics display board where team meetings are held:

When they talk about “outliers,” they mean any test result that took longer than their threshold for a given department. Before the start of their Lean journey, the lab could measure the number of test results as a percentage of their daily testing.

Many years into their Lean journey, this is now expressed as an integer – often 0 or maybe just 1 or 2 tests a day that exceed the standards for excellent care. Each individual outlier is discussed by the team (in a timely manner) to understand what the problem was in the system or the process – not laying blame on any individual.

In the spirit of Lean problem solving, they ask “why?” and often pursue a “5 whys” line of thinking (a theme that's common across Lean Healthcare, Lean Manufacturing, and Lean Startups even).

After practicing this approach, they came up with the pictured sign. Asking why (a test result took so long) helps patients tomorrow (by reducing or eliminating those causes of delay and poor quality).

The same could be true in a startup – Asking Why Today Helps Customers Tomorrow.

What do you think? Please scroll down (or click) to post a comment. Or please share the post with your thoughts on LinkedIn – and follow me or connect with me there.

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Mark Graban
Mark Graban is an internationally-recognized consultant, author, and professional speaker, and podcaster with experience in healthcare, manufacturing, and startups. Mark's new book is The Mistakes That Make Us: Cultivating a Culture of Learning and Innovation. He is also the author of Measures of Success: React Less, Lead Better, Improve More, the Shingo Award-winning books Lean Hospitals and Healthcare Kaizen, and the anthology Practicing Lean. Mark is also a Senior Advisor to the technology company KaiNexus.


  1. Mark,

    I would suspect that now they have so few outliers then it is relevant to ask why for each one since I would imagine that they are now special events. When they started the outliers would have been common, so asking why for each one would have been tampering.

    But it begs the question, how do they define their threshold?

    (And to be picky, do you mean “integer” or “single digit”? 1,000,000,000 is an integer.)

    • Rob – Yes, great point on these outliers now being (likely) due to a special cause, not a common cause.

      The threshold was defined collaboratively with their customers, based on their clinical needs. It’s not an arbitrary number.

      To be picky, 1 is both an integer and a single digit. The number of outliers they have each day tends to be both (including days when it’s zero). The number of outliers can’t be a negative integer, though :-)

      Thanks for the comment.


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