Because material costs often make up about 50 percent of total manufacturing costs, vendor selection and material acquisition gets a good deal of the operations manager’s time and attention.

Even if the material costs represent below 50% of total manufacturing costs, vendor selection and material acquisition should be extremely important for a company not only because of the costs of the inputs but also to control their quality.

It is very difficult to produce something if you don't have the correct materials; the correct quantity, the right quality and delivered on time. If any of the three previous characteristics fails, you will face serious problems.