Sourcing in transportation is a requirement. All carrier contracts have a defined term, so it is a given that at some point, new terms will need to be renegotiated. However, sourcing is much bigger than that. Optimized shippers will source regularly, even amid agreement terms, to test the market and search for opportunities for higher value. That could mean receiving the same service at a cheaper cost, improved service at the same cost, or a hybrid of the two. This paper will bring to light the hidden secretsthat carriers do not want shippers to know.