OEE = A x P x Q

Operating equipment effectiveness (OEE) is the percentage of time that equipment, when running or required for production, is producing good-quality products at an acceptable rate. It is the product of three ratios: availability, performance, and quality.

OEE = Availability X Performance X Quality

Availability = Machine availability as a percentage of scheduled uptime
Performance = Percentage of optimal production rate at which equipment operates
Quality = Quality yield percentage of all products for a given line

Industry Week says the average OEE among their Best Plant winners and finalists over the past five years is 74.1%. The highest OEE each year ranged from 90.0% to 98.8%.