Quality Control Doesn’t Work (and how to fix it)

Here is a bold statement, inspection doesn’t work; (literally bold).  Yet every organisation I have ever worked for uses and pays for quality controllers.  They can’t all be wrong can they?  What makes me think I am so right?

Have I persuaded you?

It is always better to get rid of your problems at source than rely on somebody to weed them out later.

But sometimes you need to have quality control

Sometimes you have no choice.  You need to rely on inspectors.  Can you imagine getting onto an aeroplane without somebody looking at your bags first?  How comfortable would you, as a paying customer, feel about that?  Particularly if the gentleman behind you looked a little dodgy.

So how can you make inspection work?

One of the problems with quality inspection is the “vigilance decrement”, the accuracy or speed of detection diminishes over time.

Put another way inspector’s minds wander, they start to daydream.

The less likely they are to find an item, maybe a bomb in a bag, the more likely they are to be thinking about their next holiday.

Can you imagine looking at an x-ray screen day in day out?  (Or for that matter listening to calls, or checking hotel rooms are clean?)  I would be bored out of my tiny mind.  Wouldn’t you?

So how do you spice things up?

How do you make an inspectors job more challenging and interesting?

  • Give them feedback.  Instead of just measuring their “hit rate” also measure their “false positive rate”.  How often did they think there was something there when there wasn’t? (Measures are one thing targets are something totally different)
  • Add false signals.  If only one in a billion bags has a real bomb it is hardly surprising if it gets missed.  If, however, one in a thousand does, even if it is a fake one, then chances are your inspectors will be a whole lot more alert.

Mind you, if you can, it is still better to error-proof your system in the first place.  It would be a little more than embarrassing if your fake bomb got through.

If you enjoyed this post click here to get updates delivered to your inbox
Quality Inspection

Read another opinion

Image by ThreeErin


  1. James,

    Great point. Mundane, repetitive tasks certainly put people on “auto-pilot” and make them less likely to be paying attention to every detail of what they’re doing. When you’re always doing or looking at the same thing, you tend to take shortcuts… to spice it up, something needs to zig instead of zag more frequently. Your example will, no doubt, be controversial (though I can certainly see the point) – but this can happen in a factory, at your desk, at the cash register. It’s thought provoking – how do you ensure that people are paying as close attention to detail as we need them to be.


    • James Lawther says:

      I guess the real trick is not to give them the repetitive task in the first place. Thanks for your comment


  2. Hello James

    Only those who do not understand the being of human beings would get people to do that which they simply are not in a position to do. It occurs to me that we, human beings, are wired to detect novelty – changes in the environment/context that threaten our ‘survival’ and/or present us opportunities to pursue our vital projects (survival, mate, status…).

    If I am correct a central aspect of Japanese management philosophy is to get machines to do what machines do best – the routine. And get human beings to do what they do best: creativity, novelty, pattern finding, thinking through how to deal with issues…..

    The other aspect that is important is that inspectors are human beings. To inspect properly requires a certain ease that goes along with not being in a rush. This is not what is the case say at airports where only someone inhuman would not be aware of the pressure to do the job quickly so as to avoid the ire of the passengers and the managers.

    It occurs to me that in many cases the inspection process is simply a ritual. And as such it does serve a useful function. Rituals serve to point at and bring to the forefront what matters (say quality or safety), who is involved, what parts they have to play, where power resides, penalties…..


    • James Lawther says:

      I think that is a great point Maz, why would you ask a person to do something they simply aren’t good it?


  3. Hi James,
    I think you are right that problems should be fixed at source and, in general, inspection doesn’t work for all of the reasons that you point out. However, i think there is an opportunity for “inspection” but not to just look for faults and flaws but also opportunites to improve too. Wouldn’t it also be better if this role was shared/rotated around members of a team to reduce the boredom and keep introducing fresh eyes?


Speak Your Mind