Should All Requirements Be Testable?

When product managers specify requirements for a product, we strive to formulate the requirements in such a manner that they are testable. Companies obviously want to know when they have developed a product that satisfies the requirements; to this end we want to provide testable requirements. Yet sometimes it is not practical to test a requirement directly.

Take, for example, the requirements for a new, super-reliable model of car. We might specify that the car should last seven years without repairs as long as the owner maintains the car according to a certain maintenance schedule and doesn't have a collision. But it is not possible to directly test whether the product meets these requirements without producing the car and driving it for seven years.

The difference is between requirements that are possible, in principle, to test, and those that are possible, in practice, to test. As product managers, we should strive for requirements that are possible to test in principle. We can't ignore market demands just because it's hard to test whether a product satisfies them.

Comments

Marcus Ting-A-Kee said…

For untestable requirements, you could similate approprimate tests. In your car example, this may mean stress testing components, similating weather conditions (e.g., putting the car in sub-zero conditions), starting it up 8,000 times and driving 60 miles each time etc... While not an exact match it might be close enough to give you some certainty.

Mon Feb 20, 10:17:00 AM 2006

Roger L. Cauvin said…

I agree completely, Marcus.

Just because it is not practical to test a requirement directly doesn't mean you can't test it indirectly through simulation.

A requirement always prescribes a test. Sometimes this test is not practical to carry out before releasing your product. In such cases, your team devises and carries out other, related tests that determine indirectly whether the product satisfies the requirement.

Mon Feb 20, 10:30:00 AM 2006

Why Spreadsheets Suck for Prioritizing

The Goal As a company executive, you want confidence that your product team (which includes all the people, from all departments, responsible for product success) has a sound basis for deciding which items are on the product roadmap. You also want confidence the team is prioritizing the items in a smart way. What Should We Prioritize? The items the team prioritizes could be features, user stories, epics, market problems, themes, or experiments. Melissa Perri makes an excellent case for a " problem roadmap ", and, in general, I recommend focusing on the latter types of items. However, the topic of what types of items you should prioritize - and in what situations - is interesting and important but beyond the scope of this blog entry. A Sad but Familiar Story If there is significant controversy about priorities, then almost inevitably, a product manager or other member of the team decides to put together The Spreadsheet. I've done it. Some of the mos...

5 Ways Companies Make Product Decisions

In the last blog entry, we reviewed the four problems that companies face, or are trying to overcome, as they make product decisions . Now we'll look at the ways that most companies make their product decisions. Companies that develop, market, and sell products and solutions make strategic and ongoing tactical decisions. They decide what features to include in their products, what messages they will use to communicate the value of their products, what marketing tactics they will use, what prospective customers they will target, and many day-to-day choices. Whether or not these decisions are deliberate or ad hoc, most companies use some combination of the following ways of making product decisions. (A downloadable "map" that summarizes the product decision landscape is included at the end of this article.) Customer Wants Product decisions based on feature requests, focus groups, and what prospects and customers say they want. Companies are selling products to ...

Is Customer Development Pseudoscience?

The “Science” of Lean Startup Lean startup practitioners embrace the scientific method, seeking the "truth" about what business model and strategy will lead to product success. We do so by: Formulating hypotheses Crafting and running experiments to test them Learning from the experiments Iteratively feeding our learnings back into revised hypotheses Sounds pretty scientific, at least in spirit, doesn't it? Yet this process actually neglects a key ingredient in the scientists' mode of operation. To identify what’s missing, let’s examine “customer development”. Customer Development Steve Blank is one of the pioneers of the lean startup movement. He introduced into the lean startup lexicon the term “customer development”. Customer development consists of sessions and interactions with customers to test hypotheses. For example, a product manager might interview a prospect, asking if she agrees with the product manager’s hypotheses about the problem...

Cauvin

Search This Blog