Smart Error-Proofing in Fast Food: How In-N-Out Outsmarts Quiznos with Simple Design


I was in L.A. on Tuesday, and I had a little extra time on my way to the Burbank airport, which meant a rare treat…. lunch at the famed In-N-Out. I don't mean to be that guy who tweets what he eats, but my lunch is pictured below.

in-n-out double double animal style with fries well done

The main picture I wanted to share is a simple example of perfect mistake proofing (a.k.a. error proofing or “poka yoke“). There is a possible customer error that could be made in many fast-food or deli restaurants – that error is throwing their reusable tray into the trash bin.

Ineffective organizations post signs, warnings, and exhortations. Smart organizations error-proof.

Here is the error proofing – the hole that you throw your wrapper, cup, and food waste into is round and it's SMALLER than the rectangular re-useable tray.

I didn't really fight or shove while staging this photo, but it was clear that they tray would NOT fit into the round hole. Problem prevented -it is physically impossible to trash the tray. Yes, I know you're not supposed to throw away the tray. I think this is likely obvious to MOST customers.

In comparison, most Quizno's locations merely admonish the customers. “Please Do Not Throw Away Baskets.

The Quiznos tray fits into the trash hole (which is huge). I wonder how many trays they lose?

Does Quiznos really think their customers think the hard plastic trays are disposable?? If you do accidentally drop the tray into the dirty trash and food scraps, are you likely to want to retrieve it? I maybe could have titled this post “Quiznos Thinks You Are Dumb.”

Couldn't Quiznos better use that high-visibility space with a “Thank You For Your Business” message?

You can see another example of NOT error-proofing the disposal of customer trays at our sister site,

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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. I never thought of it that way, but you’re right! One place that’s even more trash bin confusing is Chipotle (my personal favorite place for “fast” food). They have a rack that is for “recyclables” – what exactly is recyclable in their context? To me, tin foil, paper (cup, napkins), and the styrofoam flatware and condiment cups are all recyclable (in California), but that rack is not designed for those things. What they want is cans and bottles (I’ve determined), but the last time I checked it just said “please recycle”. And, in the same theme you explain above, they have the all-too-commonplace admonishment to not “discard” their trays.

    I suppose the people that think that IKEA is brilliant for making the customer assemble their own furniture think that having people sort trash is equally brilliant, but they miss the point. I think you’ve pointed this out before, but the value at IKEA is that I can drive home with a small box that fits in my car and simply (for me) make something much bigger. Assembling my own furniture in this respect adds net value for me (I don’t have to rent/borrow a truck or wait for a delivery). On the other hand, sorting trash adds no value to me unless I feel that it contributes to a better environment. Making it a painful or confusing process all but negates that will to do good.

  2. Ate at my first In-N-Out a few weeks ago. They have a LOT of culture, which seems to support finding better ways to do your work, including poka-yoke. While I am seldom in an area where they exist, they’ll be my preference. I just wish the “secret” order techniques weren’t so “secret”…

    • It’s not super secret – it’s a fun quirk about them, this “secret menu.” From their official website:

      Can also find some good stuff and pix via google.

      What I photographed and ate was the “double double animal style” where the patty is cooked in mustard and you get diced grilled onions and a few other things.

      From what I’ve read, In-N-Out has a very high “Respect for People” culture.

  3. I really love poka yoke. I wonder how many times these restaurants have the trash holes then shrink the size of the trays and don’t reconsider the trash holes? It may well be the tray needn’t be any larger than Quiznos’ for the primary function (holding food) but when you look at the whole system it is better off with a larger tray – because making the trash holes too small has other problems.

  4. my first time eating at in-N-out was about four months ago, and I just happen to notice this specific poke yoke, however my most immediate thought was that I was just being a dork :) so thank you for making me feel better, and helping me realize that there are bigger lean geeks out there. J.K thanks for all the great work Mark.
    if you ever eat at Cafe Rio, you should check out how they pack their napkins, I think is a fairly ingenious way of keeping customers from grabbing to many extra napkins.

  5. There’s a great book called – In-N-Out Burger (A behind the counter look.. by Stacy Perman) that talks about the history, family and culture of the food chain.

    I did a book review on it a while back . The chain is simply amazing and I eat there whenever I go to the west coast. I think I love watching the people work as much as I love the food.

  6. I operate quick service restaurants and people throw plastic trays and baskets into the trash all of the time. Hard to say what their motive is. I know some people think plastic burger baskets are disposable. At McDonald’s you are trained to check the bag for trays before you empty it. The loss of trays and baskets is a considerable expense if not checked.

    • Thanks for the comment Dean. Have you tried to error proof your trash bins to prevent trays from getting in? Seems like that would be more effective than having to inspect each bag of trash before it goes into the dumpster…


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