When you notice that the quality of your product isn’t a high as you’d like, what can you do?
It’s useful to start by understanding what quality means for your product: how is it defined, how is it measured, and what level is desirable.
For example, if your indicator is the number of “escaped defects” (i.e. bugs found in the customer-accessible environment) you probably want a very low number; zero is ideal but probably isn’t realistic — no matter how tight the controls are, some defects will escape. In fact, in a safe (non-life-threatening) environment, a few escapes may actually be desirable as an indicator that the controls are not excessive (i.e. wasteful).
But if you only have one metric, then you could end up focusing on that at the expense of everything else. If you only focus on preventing bugs you could spend a lot of time “gold-plating”, building far more than the customer really wants.
There needs to be one or two other metrics for balance, e.g. delivering on time (or improving the cycle time), automating as much as possible, reducing technical debt — again, it needs to make sense in your environment.
Once you have those complementary metrics in place, the question may arise: who is responsible for achieving them? In “traditional” software development there used to be a Quality Assurance team that were meant to catch all the bugs before the product was released.
The obvious problems with this are that it puts too much onus on the QA team and it’s too late in the dev process … oh, and anyone who has worked on a waterfall project will have seen that QA always gets squeezed by deadlines, so the all-important “final line of defence” has to make compromises.
It’s unfair to make the QA team solely responsible for quality when they only see the product when it’s finished — at that point, it’s very expensive to rectify a defect. Sometimes the escalating cost of fixes can lead to their prioritisation, delaying “cosmetic” defects, resulting in a bug backlog.
A better approach is to identify and tackle quality problems sooner in the development process. For an agile team, that means continuous testing, frequent feedback from the intended users, as well as code review, pair programming and other feedback loops…