Detect Instead Of Inspect


Mark's Note: I'm away on vacation through November 6… there will be some guest posts in this post during that time. Today's post is by Brian Buck, a long-time friend of this blog and a frequent contributor of some very funny Lean Memes! Check out his blog, Improve with Me.

By Brian Buck:

Before I get into the topic of today's post, let's start with a little test using the images below.


Give yourself 1 point for any statement that is true:

a. There is a square with this text: Burger King

b. There is a diamond with this text: McDonalds

c. There is a triangle with this text: Jack In The Box

d. There is a circle with this text: In-N-Out Burger

What score did you get? I would assume the readers of this blog are quite savvy about inspection and do not easily miss things. The correct answer is one.

I bet most of you caught the fact that the golden arches was missing from the images.

Did any of you struggle with having to make an interpretation on the fourth statement for the famous California restaurant? The image doesn't have the dashes as is shown in inspection statements. Does this count as “good enough” for a match or are the missing dashes a defect? How often do you think people in hospitals have to make interpretations like this every day.

By eliminating the two options above, that means either statement one or number three are true. If you haven't figured it out already, try using this question:

Which of the two remaining images have a word repeated?

I think there is a big difference between detecting and inspecting. Think of a smoke detector. It has one function and that is to look for smoke and it alarms when it finds it. By detecting for repeated words you can now see “THE” is written twice for the clown restaurant.

When we inspect for accuracy by looking over something, we often have confirmation bias and look for evidence to show that we did it right instead of specifically detecting errors. Our minds also like to gestalt things into patterns where inspect the whole instead detecting any problems in the individual parts.

If you can't error-proof and you need to add a quality step to prevent mistakes from being passed on, please try to detecting instead of inspecting!

About Brian Buck: Brian is an internal consultant at a children's hospital.  He blogs at and can be found on Twitter as @BrianBuck. He also has an essay published in Matthew E May's book The Laws of Subtraction: 6 Simple Rules for Winning in the Age of Excess Everything Guest Post: Weekend Fun The Post That Goes PING! lean.

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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. So simple and powerful! I have used the “F” game before as a similar demonstration of inspection (Give the group a few paragraphs of some silly story and have them count the F’s. They always miss the F’s in “of” for the same reasons you mention above). I will steal this one shamelessly as well :)

    I always paraphrase Deming’s “Human inspection is only 80% accurate” ideas and would love to find the source material for that. Any thoughts?

  2. I think it is zero points… The letters in quadrilateral shape of questionable equilateral-ness are all caps and the text of question #1 has lower case on all but the first letters, but it’s still an excellent way of pointing out the flaws of visual inspection.

    • Great point! I was iffy on is the square really a square but didn’t even consider the lowercase uppercase disparity!

      I made the image with text one day and the article on another. Maybe if I produced the article and image at the same time it would be consistent. There is proabably another lesson there!

      Thanks for the catch!


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