Reliable Systems

Your product is out in the wild, and even better – it’s in use by real users. You’ve got feedback and support structures in place and they are producing results. Now you need to take that feedback and incorporate it back into the product. To do this, you’re going to have to navigate the social dynamics of your organization around defects.

Any product, software or otherwise, has defects. Your shop may have a nice term to paper over it – incident, problem, ticket, errata, trouble report…. But let’s not paper over it – a defect is a defect. Developers also like to split hairs between feature requests and defects, but from a user standpoint it’s all defects. Everyone involved in product development will have their own way to prioritize defects, and to get the best results from your team’s time you need to be able to figure out which ones to address and how fast – and do so in a way that generates buy in from your development team, management, and customers.

There are an endless number of way to look at prioritization, but however you do it the discussions should include several perspectives:

• Impact, Difficulty, and Risk of defect to the end user.
• Impact, Difficulty, and Risk of even diagnosing the defect.
• Impact, Difficulty, and Risk of defect correction and deployment.

The End User Perspective

Your customers in general want and expect a defect-free product. Even if your average customer understands that all software has defects, intellectual understanding won’t overcome the emotional impact of running into a problem. Your users will generally start from the perspective that their problem is a defect in your software, it shouldn’t have been there in the first place, and you need to fix it immediately. Today would be nice.

It is very difficult to understand the value a customer places on fixing a particular issue from within the development team. Developers tend to grade defects based on the effort it takes to fix them and whether they produce an outright failure of the software. For example, few developers will get worked up over fixing a cosmetic defect such as a misspelling or alignment problem; If it’s that simple to fix, how valuable can it be? The exception to the natural cognitive bias that a problem must be hard to be worthy are problems that can crash the application or cause it to corrupt data. Few developers won’t see this as a deadly sin that must be resolved regardless of cost or risk.

Customers have a different perspective. They see just the surface veneer of your product and assume that it can never corrupt data or crash. Outright crashes have gotten rare enough that most users will refer to an error message as a crash. Because they have no idea what’s happening inside the black box that is your product, they will judge it solely on what they can see: Does it act like other applications, do the things they can see look clean and well crafted? Much like making a spelling error on the title page of your term paper can cause the entire work to be devalued, a small cosmetic error on the user interface can cause customers to doubt the correctness of your entire application.

Many end users will tend to discount defects that require long steps to produce or go away by restarting the application as long as they can convince themselves that they are at fault. This happens more often than you might expect – most users believe they don’t understand the rules behind the application and instead are using a rote procedure to accomplish their tasks. When something goes wrong, they will generally go back and try it again – possibly many times – before coming to the conclusion that there just might be a problem with the software and not with them. If the defect only presents occasionally they will usually write it off as their fault. Lest you think this behavior is limited to nontechnical users, this happened to NASA and resulted in a several day delay of the first Space Shuttle Flight.

With rare exception, if a defect isn’t judged as essential to fix by your customers, it’s probably not worth addressing prior to the next routine release. Every change to the software has consequences and takes effort that could go into something more important – to your team and your customers.

Coming Next: The Diagnostic Perspective

Come back in a few days for the next post in this series, talking about the impact, difficulty and risks of diagnosing and resolving defects.