This process involves working out what the project is really about in order to make an intelligent decision on whether going ahead with the project is a good idea. This helps elimate any wasted time, money or effort spent on any further planning.
Sometimes a quick look at an idea can reveal it is not actually as worthy as thought initially. This also involves looking at roles and responsibilites, including the Project Board, for more on the project board click here.
You can find a more in depth description of the Start-up process here