SO, just as in legal documents and contracts we have found it necessary (unfortunately) to spell out what is intended as clearly and agreeably as possible, it will serve the purpose of Quality Standards to simply provide a clear lexicon/dictionary of all important terms. How does the QUALITY PROFESSION define those terms? How does it expect to see them implemented? Whether it agrees with any (or no) common uses, within the context of the Quality Standards it will be defined specifically. The semantics - and changing linquistic landscape - of terms like "continual" vs. "continuous" will NEVER be settled. PICK ONE TERM, define it as you wish in the relevant document, and that's it.
As background, I am a Senior ASQ Member, CQA, CQE and have spent my career in international assignments and consulting. Although English is most often the "language of business" it is not the native language of most Quality System users. As a comparison, given the basis of "ISO", maybe you should consider converting ALL legitimate documents, standards and definitions into FRENCH alone. I thought not... Don't be bigotted with English either.
Deming also concluded that if he was to reduce his message to management to just a few words, it all has to do with reducing variation. See ASQs glossary of terms for Variation (What is Variation: Law of Variation).
A more common understanding of variation would provide a needed context for understanding the important distinction between continual and continuous.
In practical terms I prefer to keep the word continual improvmeent due to the fact that metrics have ups and downs: however, the trend should be positive. Continual involves continuous but continuous do not allow continual improvement. With respect to the author, I disagree, and I would prefer the standrad as is.
This was a worthwhile question and shouldn’t be dismissed as semantics. We communicate using words and if the topic is important, like quality. It is a good idea to have a very clear shared meaning of each word.
Here are my reasons for keeping continual.
All purposeful activity involves four stages: Defining, Realising, Delivering and Evaluating [DRDE]. Initially all of these are fluid and in a state of continuous improvement but nothing happens unless we freeze them for a time and let the activity achieve its outcome.
Take the defining stage. If we stay here in a fluid continuous improvement situation we never reach agreement on what the purpose of the activity is as it is constantly evolving. Therefore for practical reasons we freeze the definition or specification and have it realised and delivered and then we evaluate the whole cycle. This is when continual improvement happens. The quicker we make the DRDE cycle the higher the frequency of continual improvement but it can never be continuous even if the cycle time is in nanoseconds.
Another lesser reason for keeping continual is that it make people wonder what is the difference between continuous and continual and why does the ISO9000 series use the latter.