My Favorite Quality Tool
The overflowing toolbox
There’s a ton of quality tools out there. If you go to the Quality Tools A to Z page in the Knowledge Base on ASQ’s website, you’ll find about six dozen listed. The honor roll begins, I guess, with the Seven Basic Quality Tools promoted by Kaoru Ishikawa, a collection that includes that perennial favorite, the Pareto diagram – certainly a tool that I, as a CB auditor, see in use very often.
The Japanese have also come up with a “new seven” set of quality tools, a rather more esoteric collection – though many of you may have helped create an affinity diagram to organize ideas coming out of a brainstorming activity.
Some widely used quality tools, though, don’t make either of those lists. The 8D (Eight Disciplines) tool is one many organizations use to drive problem solving and corrective action. And a tool that I regularly recommend for performing the 4th of those Eight Disciplines – namely, root cause analysis (RCA) – is Five Whys, a deceptively simple tool for peeling back the layers of the onion so that you can dig down below the symptoms, below the proximate or immediate causes, all the way to the true root cause or causes.
It’s simple because, well, all you have to do is keep asking “Why?” (just the way a child does!) – but deceptively so, because it’s easy to go off on the wrong track if you don’t stay focused on the object of the exercise: arriving at root cause.
In fact, I’d almost call Five Whys my favorite quality tool – but it’s not quite No. 1 with me.
Poka-yoke aka mistake-proofing
No, my favorite quality tool is poka-yoke, also known as mistake-proofing, error-proofing, or (if you’re not too worried about being politically correct) idiot-proofing. (Remember, though: it has been observed that the trouble with idiot-proofing is that, no sooner have you done it, then they come up with a better kind of idiot.)
And it’s not just the cute Japanese term that I like. No, I like it because it’s the model of what a corrective action ought to be: something that makes it impossible for the problem to recur. (Technically, it can also be something that makes it impossible for the problem to be overlooked, so that it doesn’t escape; but that still means that the problem has recurred, and you may have to waste time on rework, or money on scrap.)
So, is poka-yoke a commonly used tool? Why, I bet you use examples of it almost every day.
Froms, templates and checklists
Every time you fill in a form, create a document or record from a template, or tick off items on a checklist, you’re reaping the benefits of poka-yoke. Besides offering convenience and promoting process consistency, forms, templates and checklists all have the purpose of ensuring that you don’t overlook any important items, considerations or actions.
It’s like having an SME at your elbow, prompting you: “Did you give some thought to this?” “Don’t forget to do that,” “Did you remember to cover the other?”
Quick poll for all of you auditors out there: How many findings have you raised against document control? – Ran out of fingers and toes pretty quickly, didn’t you? How much rarer a document control finding could be if every organization had (a) some well-designed document templates and (b) a comprehensive document control checklist?
They could eliminate all those common document control pitfalls: missing review or approval records, missing revision history entries, mismatched document dates and revision numbers, incorrect pagination, tables of contents with “Error! Entry undefined” lines, new documents not uploaded to the right place, and so on.
Greatest poka-yoke tool ever! Whenever you make anyone transcribe anything, it’s an invitation to error. But they can’t make that error if they just scan a barcode that’s been printed straight out of the ERP or Warehouse Management System. (Of course, they could always gun the wrong barcode; but you teach your ERP or WMS to respond “Funny, that doesn’t look like a part number to me … ?”).
Barcode scanning can be used for part numbers, serial numbers, work bench and warehouse shelf locations, even user IDs and passwords. (In addition to preventing data entry or transcription errors, it saves time too.)
The equivalent tool, in the non-hard copy domain, is simple copy-and-paste from one document to another (thank you, Microsoft!).
Poka-yoke is cool!
Here’s a fun example that I’ve seen in a facility that handles electronic components and hence has to control electrostatic discharge (ESD).
Problem: Production associates sometimes neglect to test their ESD straps before heading to their work benches. Answer: Put a fence around the production floor that associates access via a turnstile with integrated ESD tester. If they don’t test their straps and get a pass from the tester, the turnstile doesn’t turn and they don’t get in. Problem solved!
Another ESD control measure that employs poka-yoke is called a constant monitor. Instead of merely plugging a wrist strap into the grounding point at the work bench, it’s plugged into the constant monitor which is already connected to ground. The monitor continually checks for a good connection with the wrist strap. If the strap should happen to get disconnected, the monitor immediately starts beeping, annoyingly and incessantly, until something’s done about it.
Poka-yoke is an ideal tool for both corrective and preventive actions; and it’s cool, too! Give your creativity a chance for some exercise by designing a poka-yoke solution to your next problem!
Author: Rick Hill, TL 9000 Program Manager @RichardHillQMS