Key Performance Indicator. A metric that describes, in part, the performance of a manufacturing facility. Examples could be percent downtime, percent of product within specifications, energy use per unit of output, etc.
If you work in the food industry and are concerned about regulatory compliance, check out IPACT's HACCP application. (details...)
How much does it cost for your plant to be down or crippled for a day? A week? A month? Maybe more than the cost of your automation system. (Read how simulation avoids downtime...)