Common Mistakes: Functional Specification for Web Development

In the IT industry the standard criterion for a functional specification is 'can you write a test plan from it?.    You should be able to sit down with the functional spec, write a test plan with data and expected results.

Not only is it a good criteria, its not a bad idea to give it a shot.  This way statements like 'must be easy to use' quickly get examined and rejected.  How do you test that?  Answer: you can't because its subjective.

It is vital that this criterion is applied early because the functional spec is a contractual document.  If you accept a spec with 'must be easy to use' and quote against it then in due course some client might decide not to pay on the basis of non-compliciance.  You may laugh but I once worked with an IT functional spec that said 'provide a complete banking solution'.  That was put in as marketing waffle but in the end we settled out of court for a six-figure sum.

Bob
Textor