Mistake-Proofing – The Poka-Yoke of Usability

How do we go about mistake-proofing our product design? As we're looking at our user process, we can use a quality method that's well-used in manufacturing production: poka-yoke (mistake-proof).

Download the guidelines and checklist, and then follow-along with the podcast.

Mistake-Proofing the User Process

Get this one-page guideline and checklist to get started.

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Below are the examples we talked about in the podcast. Share with us in the comments: what is another example of everyday uses of mistake-proofing that you notice?

Example  Inspection Type (Who & When)  Inspection Methods   Type of Alerts 
Computer cables are designed to only fit together one way.  


Source Inspection check  Physical method   n/a 
We have self-assembly furniture, and we check the contents of the box against the parts list in the instructions before we start assembling it.  


Successive inspection   Grouping and Counting method   n/a 
Passing our technical report through a spell-checker or Grammarly before we publish it 


Self-inspection   Information enhancement  n/a 
Powered miter saws require a single-handed a brake release button and trigger that need to be pushed at the same time. 


Source inspection check   Step-sequence method    n/a 
I hear buzz sound when I don’t remove my credit card from the machine after it’s done reading it. 


Self-inspection   Information enhancement   Warning function 
I turn off the engine in my car while it’s still in drive. The car gives me a jingle, and a bright orange message appears in the dashboard: I’ve forgotten to put the car into Park. 


Source inspection   Physical method (sensor)  Warning function 
The self-checkout system at the grocery store won’t let me scan another item until I’ve placed the previous item into the bagging area.  Source inspection  


Grouping and Counting method   Control function  



Also visit Episode 29: Types of Design Analyses possible with User Process Flowcharts

Definitions of poka-yoke dimensions are adapted from:
Tague, Nancy R. “Mistake Proofing.” The Quality Toolbox, 2nd ed. ASQ Quality Press, 2005, pp. 351-356.

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