0. What's the matter with requirements ?

In my experience, many problems arising from the little care in requirements gathering are mainly due to these five factors:

• Pre-judgments: we believe we know how to do the right thing before we even realize what we have to do,

• We do like to "settle" things "later",

• End users often do not know exactly what they want, or express themselves in their own way and often different users have conflicting requirements,

• The requirements now are constantly changing: as soon as we catch some, some other requirement has already changed,

• Often there are organizational or "political" factors involved (ie. we listen more to the requirements of a manager who will never use the system rather than the requirement of the user who will use it 10 times a day).