Welcome to my blog for all things related to business quality (processes, systems and ways of working), products and product quality, manufacturing and operations management.

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The pros and cons of ‘Zero Defects’

Zero Defects is the approach to quality that was developed and promoted by the guru Philip B. Crosby in his book ‘Quality Is Free’.

Forget Six Sigma – this is ‘Infinite Sigma’!

It’s a way of thinking about quality that doesn’t tolerate errors or defects and continually strives to improve processes and prevent errors so that work is always done correctly without needing repetition or rework or generating waste; this is Crosby’s philosophy of ‘right first time’.

These phrases have the benefit of being unambiguous; ‘Zero Defects’ and ‘right first time’ mean exactly what they say.

Think of this issue the other way round; the alternative to Zero Defects is that a certain level of defects is seen as normal or acceptable, as implied by the Acceptable Quality Limit approach; Crosby took a strong line against AQLs for precisely that reason, he saw them as a “commitment, before we start the job, that we will produce imperfect material”.

Zero Defects is based on four key principles:

  1. Quality is simply conformance to requirements, not some sort of measure of performance or ‘goodness’
  2. It is always cheaper to do the job right the first time than to correct problems later (quality should be ensured through prevention, not appraisal)
  3. Quality is measured in monetary terms (the price of non-conformance)
  4. The performance standard must be Zero Defects, not “that’s good enough”.

The key word for achieving Zero Defects is prevention, you don’t get ‘ZD’ by simply taking corrective actions to rectify existing problems, you have to stop them occurring in the first place. And, as I have mentioned before, taking preventive actions is much harder than taking corrective actions.

The case for Zero Defects

Zero Defects addresses the apathy that you often come across: “There will always be errors, there’s nothing you can do to prevent them”; why do we accept this statement for product manufacturing or software design but wouldn’t accept it from our surgeon as we entered the operating theatre, or in our bank accounts?

Crosby explains that defects represent a cost that is often hidden (inspection, waste/scrap, rework, lost customers, etc). By eliminating defects these costs are sufficiently reduced that the savings more than pay for the quality improvement programme; hence his assertion that ‘Quality is Free’.

The case against Zero Defects

Zero Defects is controversial because it’s so difficult to achieve; some people claim it’s ridiculous and counter-productive to have a target of zero that will rarely be attained. They believe it will lead to excessive inspection costs and demoralised staff who keep ‘failing’.

If implemented without sufficient thought it could even cause defects because of the extra stages of increasingly rigorous and expensive inspection and handling of the products.

It also incurs the wrath of people who hate slogans or ‘campaigns’.

Zero Defects is a difficult sell.

In many regards these criticisms, although well-meant, miss the point. Crosby didn’t expect that everyone adopting Zero Defects would always achieve it, or that residual defects should be seen as failings by an individual or group. Nor did he advocate commercially unjustifiable amounts of inspection. As with many areas of quality management it’s about the philosophy and the journey you take from where you are now to being a better business, it is the “attitude of defect prevention”.

When your goal is zero defects it sets a standard against which all your processes can be assessed. It’s about continually striving to work better and not being satisfied with the status quo.

It’s also worth bearing in mind that he didn’t intend ‘ZD’ to always stand alone, it formed just 3 steps out of a 14 step quality improvement programme.

So how do you do it?

I’d love to elaborate but it’s not something that I can easily summarise in a blog. His book describes ‘how to’ in detail, so may I refer you to ‘Quality is Free: The Art of Making Quality Certain’ by Philip B. Crosby?

However, you might be interested in some of his related concepts such as how to assess the real Cost Of Quality, so I’ll talk about these in future blogs; watch this space!

5 comments to The pros and cons of ‘Zero Defects’

  • Tom,

    Great post. Six Sigma espouses “perfect processes” as a euphemism for Zero Defects. I have always viewed ZD as a goal, not much of a reality. I have seen that as you improve, you reach a point of diminishing returns where the cost to reach 99.99% is 10 times the cost to reach 99%. I understand that prevention is the key, but reality is that problems exist, and to reach ZD existing problems must be corrected in addition to preventing new ones.

    Jim Wells

  • Tom G

    Jim, you are quite right of course, it’s an attitude of intolerance to defects and determination to prevent them (as opposed to accepting that defects happen and not really trying to get rid of them all).

    No, you won’t always succeed and no, the defects won’t always be zero, but as you say it is a goal.

    Many thanks for the comment; much appreciated.


  • Daniel MRaj

    Zero Defect is the backbone and thee should be no compromise to defects

  • Tom G

    Daniel, you are right, in the ideal world there shouldn’t be compromises. Zero Defects means what it says. We are told that any defects – however explicable or ‘understandable’ or exceptional – are meaningful and must be investigated and their root causes eliminated.

    I always try to take a pragmatic line to avoid going to extremes and putting disproportionate effort into Quality Assurance; “how do we improve where we are now?” “Let’s make things better than they were and lets go through that improvement process repeatedly.” (Of course, for safety-critical applications you will apply more rigorous standards and put in more QA than for less crucial applications, even though all systems can benefit from ZD if applied correctly.)

    Thanks for your comments.


  • Phaswane Moroatshehla

    Zero defects.

    This is in my opinion a driver for excellence. Excellence is achievable, as there is a saying, “where there is a will, there is a way.”

    The Criteria for Perfoemance Excellence aligned to the Malcolm Baldridge National Quality Award is indicative that through intent, organisations can achieve excellence, and this for me is a road towards zero defects.

    Deming’s fourteen principles indicates the importance of involving every employee in the quality effort. This again is an effort towrds ‘Zero Defects’.

    Zero defects is achievable, we just need to open the minds and understand the customer requirements, and then apply our minds to achieveing the customer requirements – we then should achieve zero defects. To produce quality products, services or results requires understanding the customer requirements to the full, and meeting those requirements – to produce ‘Zero Defects’. Sometimes customers might not understand the exact product,service or result, thus the involvement of different employees in the quality effort will ensure some people probe the customer to get to the core of what the customer wants, so that it is delivered as required. Also, training and development is key to quality, to ensure the frontline(customer interaction) staff understand the requirements and the designers design accordingly (thus our process management staff needs to be polished in terms of skills).

    I am very passionate and interested in the quality management field, and thus this long but shortened version of my input.

    Let’s get the discussion going.


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