A Proof of Concept (POC) is a small exercise to test a discrete design idea or assumption. Software developers tend to do POCs instinctively when they experiment with technology.  An example of a POC is testing whether one technology talks to another.  To be deliberate, a POC should clearly state what it is to be proven and to what degree.   The results of a POC need to be measurable so that they can be fed into the decision making process.  Decisions should be based on thresholds such as a performance level that is acceptable.