REQUIREMENTS !

There are many steps between the real needs, the requirements you write, how the thing is made. * What the user really needs * What the user knows What the user thinks * What the user actually says to you What you hear What you understand What you memorize * What you write down What the developer will read * What the developer will understand etc.

At the end of it, the job of us "requirements gatherers" is to ask the right questions.  In my experience, the really big issues arise basically from three kinds of errors : - All the questions you forgot to ask, - Some questions that you asked, didn't get (or understand) the answers well, and were afraid of asking again (and again, and again, and again), - Some questions you asked in the wrong way (so the user was "forced" to give you an incorrect answer).

A few words about the different kind of systems, just so you know in which kind of trouble you are when you start gathering requirements :-) SIMPLE What it is: you can see clearly all the connections between cause and effect . How to handle it: it is usually easy. COMPLICATED What it is: there are cause - effect connections, but it's not easy to see them. There is never a unique solution. How to handle it: ask questions to the experts (if there is any). COMPLEX What it is: it is made of many pieces, and they are highly interconnected. The output is usually part of the system itself and influences it, so it's difficult even to ask yourself the right questions. How to handle it: test some small parts and see what it happens (someone calls it "dance with the system.") CHAOS What it is:  high uncertainty, no apparent cause and effect and ... when some rule seem to apply, it will probably change very rapidly. How to handle it: run away !