Skip to main content

Quality != Quality


Anne-Marie Charrett delivered a beta version of her Testbash Manchester keynote at the Cambridge Tester meetup this week. Her core message was that quality and testing are not the same thing:
  • there are non-testing aspects of software development that contribute to product quality
  • there are non-product aspects of quality which should be considered in software development.

A theme of the talk was that customer benefit could be threatened by the second of these, by factors such as code hygiene, speed of delivery, and time to recover after a failure in production. Testers, and others in software development, were urged to reframe their view of quality to encompass these kinds of activities. A Venn diagram represented it like this:


Interesting, but it didn't quite hang together for me. I slept on it.

In the morning, I found myself thinking that what Anne-Marie was trying to visualise really had two notions of quality, and they were not the same. Perhaps she could move from a two-way to a three-way relationship between product quality (features, performance, usability and so on), production quality (for the non-product stuff around producing the software), and customer benefit. (Although I prefer business value rather than customer benefit because the business might prefer things that don't give value to the customer at some times.)

Here's how I've tried to sketch that:


The sweet spot is work that improves the way the software is produced, improves the software and adds value for the business. For example, changing from a product implemented in two languages to a product implemented in a single language could enhance in-product consistency and performance, simplify toolchains, and reduce IDE licensing costs.

But the tripartite division gives other potentially interesting intersections too. There's the traditional new feature which drives an increase in sales (product quality/business value) and then there's situations like moving from weekly to daily drops of a core component to internal teams which removes wasted time on their side (production quality/business value).

Anne-Marie asked for feedback on her talk so I pinged her a few notes along with a sketch of my idea and she incorporated some of it into the keynote.


Which is gratifying and all that but while my model might be considered an iterative improvement on hers, it's not short of its own quirks. The intersection I haven't mentioned yet (production quality/product quality) could be encountered when ancient build servers are replaced, enabling newer libraries to be used in the product, but adding (at least, at that time) no value.

The caveat, at that time, is interesting because it reflects the idea that there's a granularity effect at play. The example just given, at a certain temporal granularity, adds no value. But once new features that build on the new library are implemented, value is added. Zoom out to a wider time perspective and the action of updating the build server can sit in the sweet spot.

There's other ways in which this model is fuzzy: in a continuous deployment world, the boundary in the pipeline between the product and the production of the product becomes harder to define. Also, there's no good way to represent stuff that's actively detrimental to business value.

And there's ways in which our viewpoint (biased to the technical) can distort the relative importance of our interests too. Remember that business value can be generated without any involvement of the development staff: dropping the price of the product might drive sales and increase overall revenue.

Your perspective on the model alters the value of the model. Quality may not be whatever you think it is. Stay humble.
Images: Nick Pass and Dan Billing (via Twitter)

Edit: This post blew up a bit on Hacker News. The views expressed there on what quality is or isn't, the ease with which quality can be achieved, and the notions of quality as subjective or objective distinction are interesting to see. Anne-Marie used Weinberg's definition of quality in her talk and I recently wrestled with that in In Two Minds.

Comments

  1. It's so helpful to me to see ways to visualize quality, and this captures so many aspects. Thank you for sharing it!

    ReplyDelete
    Replies
    1. Cheers, Lisa.

      I've had a few goes at understanding what I think quality might be. (Or more accurately, understanding what I don't understand.)

      Delete
  2. Thanks to Lisa for the slides.
    And thanks to James for the post. You are once again fueling my wilingness to write about basic things in testing :-).
    Here is how I describe the things to "young testers". https://lazytesterua.blogspot.com/2017/10/expectations-requirements-reality.html

    ReplyDelete
  3. I don't think the quality vs testing meme is presented as in this blog post. Usually quality is pitted *against* testing, i.e., quality is better than testing. In fact, these aren't either or.

    In the software industry, Bach-Bolton type testing is almost unknown. The quality vs testing meme is used to justify that.

    Discussions on quality vs testing would be welcome, *if* there was a strong understanding of testing. No good tester would argue against overall quality improvement. However, in most cases, quality is offered as a (better) choice. That is incorrect.

    ReplyDelete

Post a Comment

Popular posts from this blog

Can Code, Can't Code, Is Useful

The Association for Software Testing is crowd-sourcing a book,  Navigating the World as a Context-Driven Tester , which aims to provide  responses to common questions and statements about testing from a  context-driven perspective . It's being edited by  Lee Hawkins  who is  posing questions on  Twitter ,   LinkedIn , Mastodon , Slack , and the AST  mailing list  and then collating the replies, focusing on practice over theory. I've decided to  contribute  by answering briefly, and without a lot of editing or crafting, by imagining that I'm speaking to someone in software development who's acting in good faith, cares about their work and mine, but doesn't have much visibility of what testing can be. Perhaps you'd like to join me?   --00-- "If testers can’t code, they’re of no use to us" My first reaction is to wonder what you expect from your testers. I am immediately interested in your working context and the way

Meet Me Halfway?

  The Association for Software Testing is crowd-sourcing a book,  Navigating the World as a Context-Driven Tester , which aims to provide  responses to common questions and statements about testing from a  context-driven perspective . It's being edited by  Lee Hawkins  who is  posing questions on  Twitter ,   LinkedIn , Mastodon , Slack , and the AST  mailing list  and then collating the replies, focusing on practice over theory. I've decided to  contribute  by answering briefly, and without a lot of editing or crafting, by imagining that I'm speaking to someone in software development who's acting in good faith, cares about their work and mine, but doesn't have much visibility of what testing can be. Perhaps you'd like to join me?   --00-- "Stop answering my questions with questions." Sure, I can do that. In return, please stop asking me questions so open to interpretation that any answer would be almost meaningless and certa

Not Strictly for the Birds

  One of my chores takes me outside early in the morning and, if I time it right, I get to hear a charming chorus of birdsong from the trees in the gardens down our road, a relaxing layered soundscape of tuneful calls, chatter, and chirrupping. Interestingly, although I can tell from the number and variety of trills that there must be a large number of birds around, they are tricky to spot. I have found that by staring loosely at something, such as the silhouette of a tree's crown against the slowly brightening sky, I see more birds out of the corner of my eye than if I scan to look for them. The reason seems to be that my peripheral vision picks up movement against the wider background that direct inspection can miss. An optometrist I am not, but I do find myself staring at data a great deal, seeking relationships, patterns, or gaps. I idly wondered whether, if I filled my visual field with data, I might be able to exploit my peripheral vision in that quest. I have a wide monito

Testing (AI) is Testing

Last November I gave a talk, Random Exploration of a Chatbot API , at the BCS Testing, Diversity, AI Conference .  It was a nice surprise afterwards to be offered a book from their catalogue and I chose Artificial Intelligence and Software Testing by Rex Black, James Davenport, Joanna Olszewska, Jeremias Rößler, Adam Leon Smith, and Jonathon Wright.  This week, on a couple of train journeys around East Anglia, I read it and made sketchnotes. As someone not deeply into this field, but who has been experimenting with AI as a testing tool at work, I found the landscape view provided by the book interesting, particularly the lists: of challenges in testing AI, of approaches to testing AI, and of quality aspects to consider when evaluating AI.  Despite the hype around the area right now there's much that any competent tester will be familiar with, and skills that translate directly. Where there's likely to be novelty is in the technology, and the technical domain, and the effect of

Postman Curlections

My team has been building a new service over the last few months. Until recently all the data it needs has been ingested at startup and our focus has been on the logic that processes the data, architecture, and infrastructure. This week we introduced a couple of new endpoints that enable the creation (through an HTTP POST) and update (PUT) of the fundamental data type (we call it a definition ) that the service operates on. I picked up the task of smoke testing the first implementations. I started out by asking the system under test to show me what it can do by using Postman to submit requests and inspecting the results. It was the kinds of things you'd imagine, including: submit some definitions (of various structure, size, intent, name, identifiers, etc) resubmit the same definitions (identical, sharing keys, with variations, etc) retrieve the submitted definitions (using whatever endpoints exist to show some view of them) compare definitions I submitted fro

Testers are Gate-Crashers

  The Association for Software Testing is crowd-sourcing a book,  Navigating the World as a Context-Driven Tester , which aims to provide  responses to common questions and statements about testing from a  context-driven perspective . It's being edited by  Lee Hawkins  who is  posing questions on  Twitter ,   LinkedIn , Mastodon , Slack , and the AST  mailing list  and then collating the replies, focusing on practice over theory. I've decided to  contribute  by answering briefly, and without a lot of editing or crafting, by imagining that I'm speaking to someone in software development who's acting in good faith, cares about their work and mine, but doesn't have much visibility of what testing can be. Perhaps you'd like to join me?   --00-- "Testers are the gatekeepers of quality" Instinctively I don't like the sound of that, but I wonder what you mean by it. Perhaps one or more of these? Testers set the quality sta

Vanilla Flavour Testing

I have been pairing with a new developer colleague recently. In our last session he asked me "is this normal testing?" saying that he'd never seen anything like it anywhere else that he'd worked. We finished the task we were on and then chatted about his question for a few minutes. This is a short summary of what I said. I would describe myself as context-driven . I don't take the same approach to testing every time, except in a meta way. I try to understand the important questions, who they are important to, and what the constraints on the work are. With that knowledge I look for productive, pragmatic, ways to explore whatever we're looking at to uncover valuable information or find a way to move on. I write test notes as I work in a format that I have found to be useful to me, colleagues, and stakeholders. For me, the notes should clearly state the mission and give a tl;dr summary of the findings and I like them to be public while I'm working not just w

Build Quality

  The Association for Software Testing is crowd-sourcing a book,  Navigating the World as a Context-Driven Tester , which aims to provide  responses to common questions and statements about testing from a  context-driven perspective . It's being edited by  Lee Hawkins  who is  posing questions on  Twitter ,   LinkedIn , Mastodon , Slack , and the AST  mailing list  and then collating the replies, focusing on practice over theory. I've decided to  contribute  by answering briefly, and without a lot of editing or crafting, by imagining that I'm speaking to someone in software development who's acting in good faith, cares about their work and mine, but doesn't have much visibility of what testing can be. Perhaps you'd like to join me?   --00-- "When the build is green, the product is of sufficient quality to release" An interesting take, and one I wouldn't agree with in general. That surprises you? Well, ho

Make, Fix, and Test

A few weeks ago, in A Good Tester is All Over the Place , Joep Schuurkes described a model of testing work based on three axes: do testing yourself or support testing by others be embedded in a team or be part of a separate team do your job or improve the system It resonated with me and the other testers I shared it with at work, and it resurfaced in my mind while I was reflecting on some of the tasks I've picked up recently and what they have involved, at least in the way I've chosen to address them. Here's three examples: Documentation Generation We have an internal tool that generates documentation in Confluence by extracting and combining images and text from a handful of sources. Although useful, it ran very slowly or not at all so one of the developers performed major surgery on it. Up to that point, I had never taken much interest in the tool and I could have safely ignored this piece of work too because it would have been tested by

The Best Laid Test Plans

The Association for Software Testing is crowd-sourcing a book,  Navigating the World as a Context-Driven Tester , which aims to provide  responses to common questions and statements about testing from a  context-driven perspective . It's being edited by  Lee Hawkins  who is  posing questions on  Twitter ,   LinkedIn , Mastodon , Slack , and the AST  mailing list  and then collating the replies, focusing on practice over theory. I've decided to  contribute  by answering briefly, and without a lot of editing or crafting, by imagining that I'm speaking to someone in software development who's acting in good faith, cares about their work and mine, but doesn't have much visibility of what testing can be. Perhaps you'd like to join me?   --00-- "What's the best format for a test plan?" I'll side-step the conversation about what a test plan is and just say that the format you should use is one that works for you, your coll