Software product success.
You knew it would happen eventually, the big ten rules of writing requirements has become the big twelve rules. Maybe scope creep isn’t such a bad thing after all. Writing style plays an important role in writing requirements too.
We ran a series called Writing Good Requirements – The Big Ten Rules in May 2006. Bloggers are notorious for not being able to count. We had ten rules at the time, and now we’re adding an eleventh. Writing Correct Requirements may have been the unwritten rule, but now we take a look at it.
One of the ten big rules of writing a good MRD is writing passionate requirements. What in the world is a passionate requirement [they were all wondering]? When you believe in the product, are committed to the work, and aren’t bored, you can write passionately. The goal of a requirement is to create sustained understanding. A dry document can create understanding, but an engaging document will sustain it.
One of the ten big rules of writing a good MRD is writing atomic requirements. Just as verifiable requirements must be concretely measurable as having been met or not, so must atomic requirements. If a requirement has multiple elements that can be implemented separately, it is not atomic.
One of the ten big rules of writing a good MRD is writing verifiable requirements. Verification is both a function of having a precise goal, and having the ability to affordably measure the requirement. A precise goal is a verifiable requirement if we can clearly answer “yes” or “no” when asked if the requirement has been implemented. We also face the practical realities of being able to measure the results profitably.
One of the ten big rules of writing a good MRD is writing unambiguous requirements. Ambiguity is a function of communication. The writing can be generically ambiguous, or ambiguous to the writer. A requirement could be precise in intent, but ambiguous in interpretation by the reader. Understanding our audience is as important as precision in language. We write unambiguous requirements because misinterpretation of requirements is the source of 40% of all bugs in delivered software.
One of the ten big rules of writing a good MRD is writing consistent requirements. Consistency within an MRD has two dimensions that are important to requirements – logical consistency and grammatical consistency. There is also the element of writing an MRD that is consistent with other documentation – external consistency.
One of the ten big rules of writing a good MRD is writing complete requirements. We identify problems and opportunities in the market. We determine that one of these problems is valuable enough and practical to implement. Then we have to write the requirements, and make sure that the requirements will completely solve the targeted problem.
One of the ten big rules of writing a good MRD is writing attainable, or realistic requirements. These are requirements that can be practically implemented, by our team, according to our schedule. Practicality is a function of the skills of our team members, the costs that we face to implement a particular requirement, and the circumstances in which we are developing. Agile proponents use the phrases ‘people trump process’ and ‘politics trumps people.’ To write attainable requirements, we have to think about our people and our political situation.