has been so kind as to publish one of my how-to's:
Many sourcing expeditions are doomed to failure because the sourcer “assumes” they have found what the customer wants. The fact is, in these instances, the sourcer hasn’t asked enough questions of the customer on the front end of the process to know what the customer wants. This is because they do not possess the depth of experience in sourcing to know what questions to ask.
Read the whole article here