Marshmallow Challenge

What We Learn When We Build Spaghetti Towers

As part of a training on root cause analysis, a group of King County employees tried the Marshmallow Challenge in early December.

The challenge is simple. Teams get 20 sticks of spaghetti, one jumbo marshmallow, one yard of string, and one yard of masking tape. Using only those items, they have to make the tallest free-standing structure they can in under 18 minutes.

The catch is that the structure has support the marshmallow on top.

If you aren’t familiar with the Marshmallow Challenge, go watch this seven-minute video. (Seriously, go check it out. We’ll wait.)

In this context, “prototyping” means PDCA: (quickly) plan a structure that might work for this challenge, do it, check how high it stands or if it stands at all, adjust it to make it stand taller. And repeat as many times as you can in 18 minutes.

Here are some other Lean lessons that King County employees discovered when they did the challenge:

What works best isn’t necessarily what’s most carefully planned

This team had worked for 17 minutes on a tower with an elaborate supporting base intricately connected to the upper spire. It was cleverly designed and painstakingly executed. And it didn’t work.

So, in the last few seconds—SNAP!—success. This team won by about one-half inch.

Team members: Debbi Linebarger, Andrew Currier, Janice Rahman, and Kuno Hollriegel

Improvement means risking failure

This team had a totally viable structure. It looked good. It stood upright (more than half the battle). It would have been understandable if this team had stood pat, maybe only making slight tweaks to their design.

But this team wanted real improvement. So they tore their structure down to the studs and made some big changes.

The “Oh, please…Try it!” at the end is the essence of kaizen.

Team members: Vicki Oyadomari, Lori Heniff, and Kara Cuzzetto


Sometimes Life Gives you Red Herrings

After they’d built their towers, the teams practiced some root cause analysis, digging into how they might have made taller towers. One thing both teams noticed was that they didn’t do much at all with the string. Here’s the way one team assessed it:


“Not sure how to use string.”


When asked about uses he’s seen for the string in the past, Lean Specialist Steve Beauchamp, who conducted the training, said this:

“Sometimes we are given tools and or supplies that are red herrings and we can spend a lot of time trying to figure out what to do with them. The string may be just that. I rarely see people use the string though it is part of the exercise. It is for those out-of-box thinkers mostly.”

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