Thinking Backwards or Forwards

I've heard references to a new style for documenting requirements. Greg Young talks a little about it in his post on business requirements at CodeBetter.com



I think he is onto something, as it is usually fairly obvious that business customers can handle some pretty complicated procedures and process flows, so why do they struggle with a machine, or state, based approach?  The difference I suspect is that they focus on the action and not the state. The specs he describes are centered around a state, lists an action and only then describe the behavior that results from said action; let's write it thusly:




State ->Action->Behavior.



I'd be willing to bet that the users are really thinking like this, "I want it to do X (Behavior) so I have to push the yellow button (Action) but it only works if the red light is on (State), or



Behavior<-Action<-State





The style of documenting has enough in common that they understand what is being asked for even if, to them, it is listed backwards. As an aside, another major difference is I've never had a business user ever want to have a meta-discussion on how they think, so we tend to have to take it into account when designing the requirement gathering process but that will have to wait for its own post.