Six Sigma in purchasing

Acquisition process, like any process, is composed of a sequence of operations that transform inputs into outputs and adds value. When we talk about entries we think of course about suppliers and performance of their products, including their evaluation. Evaluating is ISO 9001 or 16949 IATF requirement.
Six Sigma is a 5 steps methodology (Define - Measure - Improve - Control) and can help in improving the acquisition process.
Examples of measurable indicators in acquisitions can be: the minimum supply time, index of price decreasing, level of usage of warehouses, bills payment time, etc