It was a sentence that came without much conscious thought at the end of another post  that’s had me thinking – yeah, consciously – for a couple of weeks. While I was reflecting on my own view of and reaction to the quality of some stuff I’d bought, and which had failed, and trying to project this onto my day job, I asked:

What qualities constitute quality for [the people concerned]?

At its core this was simply restating Weinberg’s elegant and efficient definition of quality as value to some person – often extended to some person that matters – but I found myself going back to the phrase, chewing it over and wondering whether the idea of breaking out the singular value into the plural qualities was a useful addition:

Quality is the qualities that provide value to some person.

After consideration, I think that what I like about it is that it draws out explicitly the point that the quality of a piece of software is intrinsically made up of a set of its, usually numerous, individual characteristics and that for different people this will be different. Indeed, for a given application and any given two people they need not even intersect. A particular quality of the software may itself be a union of other qualities, some of which are shared across qualities.  (I find it interesting that with this restatement I’ve started thinking in terms of sets of people, features, characteristics.)

It may be hard to predict which qualities will be popular in general and, in some cases, what the all of the qualities even look like. And qualities are not equal: certain of them will be more important to some individuals; some will be more important than others to a given person, even to the extent that a single quality may outweigh all others. They may be feature-level items, very specialised capabilities, performance, stability, general usability concerns, technical support or anything else to do with the product.

I don’t claim that these are new thoughts – and they aren’t – but I haven’t found it stated this way elsewhere.  Is there a precedent? Is there any value in it?