Skip to main content

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
Post a Comment

Popular posts from this blog

What Product Managers Can Learn from the Apple iPod

The Story When Apple unveiled its iPod digital music player back in October 2001, I dismissed it as a  parity product . I already owned the Cowon iAUDIO CW100 MP3 player, loaded with my favorite tunes. There was Apple, generating great hype over the iPod as if it were a breakthrough product. The idea of a portable digital music player was nothing new. The first mass-produced MP3 players came out in 1998. In late 2001, the concept may have been new to a lot of Apple customers, but it wasn't new to me. I proudly showed my MP3 player to friends when they gushed about the iPod. Thus Apple's iPod was not an innovative product in and of itself. Years later, however, I realized the significance of ecosystem of which the iPod was a part. Apple had released iTunes (with technology purchased from  SoundJam MP ) and created the iTunes Store for finding and downloading music. Unlike Napster , it was a safe and legal way of distributing and acquiring music. The prior way of playing
2 comments
Read more

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
32 comments
Read more

Interaction Design: the Neglected Skill

Your product development organization has a big, gaping hole in it. (Be prepared to feel defensive as you continue reading.) One of the most important roles in product development is the role of interaction designer. An interaction designer designs how the users will interact with the product and conceptualize the tasks they perform. He decides whether, for example, the user interface will be command driven, object oriented (clicking on objects then specifying what to do with them), or wizard based. The interaction designer decides the individual steps in the use cases. Every company has one or more people that play the interaction designer role. Usually, those people have little or no expertise in interaction design. Sadly, they typically don't even realize how unqualified they are. Let's see who typically plays the role at companies. Engineer . An engineer is an expert on building what is designed. Yes, an engineer may know how to design the internal structure of the hardware
8 comments
Read more