Mohammed Hamed Ahmed Soliman 
Toyota Production System Concepts [EPUB ebook] 
Understanding OEE in Lean Production

Overall equipment efficiency (OEE) shows how well a machine or equipment is performing by comparing the number of defect-free products or parts it makes to its maximum potential output. The OEE of a machine or process at 100 percent means that it is working at its highest possible capacity without any errors.
There are three things that make up OEE: availability, performance, and quality. When the actual output is less than expected, professionals can identify areas of improvement in three factors and make changes that maximize the capabilities of the current process, resolve issues, and enhance productivity.