what is the most important tool for determining how the resources should be integrated?

Answer 1

I suppose this depends on application. If the situation is for business, then I would say margin is the most important factor. Is this a profitable endeavor or not? If not, does it have future earning potential (i.e. marketing value)

Answer 2

Understanding why people use your product or service and then directing resources to maximize that aspect. Also, knowing where your weak spots are and using resources to improve those areas is critical to fending off competition.