7.8. Reliable Specifications: An Oxymoron?

Written requirements can promote the illusion that the real requirements are understood and well-defined, and can (early on) be used to reliably estimate and plan the project. This illusion is more strong for non-software developers; programmers know from painful experience how unreliable it is. This is part of the motivation for the opening quote by Goethe.

What really matters is building software that passes the acceptance tests defined by the users and stakeholders, and that meets their true goals (which are often not discovered until they are evaluating or working with the software).

Writing a Vision and Supplementary Specification is worthwhile as an exercise in clarifying a first approximation of what is wanted, the motivation for the product, and as a repository for the big ideas. But they are not—nor is any requirements artifact—a reliable specification. Only writing code, testing it, getting feedback, ongoing close collaboration with users and customers, and adapting, truly hit the mark.

This is not a call to abandon analysis and thinking, and just rushing to code, but a suggestion to treat written requirements lightly, and continually—indeed, daily—engage users.