Benefits are good but Commitments on is better

It is relatively affordable to prepare a business case. It takes longer for it to be of good quality (read: reliable) and a little less time if the quality can be poor (read: too optimistic).

Anyway Business Cases are rarely in play for very long. In many places they are forgotten after the project is approved. Fewer places review it at every gate in the project model. Even fewer sites are updated on an ongoing basis as all get wiser. Finally the very few places make a review long after project completion to follow up on the promised effects.

Anyway it's all not of much use if the benefit's or effects are seen as something only the project must produce - something the project should Push forward. The reality shows that without someone to demand Benefits or effects, there is rarely much chances of success - some must Pull too.

Anyway it does not help that much if those who must demand are not committed.

Therefore, a good business case should have more signatures: 1) the signature of the costs and resources may be used for the agreed deliverables 2) signatures that somebody has put their head on the block that if they get the deliverables they are accountable for the benefit's.