Overall Equipment Effectiveness

OEE or Overall Equipment Effectiveness is a measure of how effective productive asset are being utilized. The parameter for measuring OEE are Unplanned Downtime, Loss of Capacity, Inefficiency and product quality as shown in the figure below.
In order word, the asset performance is the function of planned downtime, unplanned downtime, efficiency losses & quality losses. Therefore in order to maximize asset contribution, we need to manage those parameter properly. That is why Asset optimization is very important in order to achieve higher asset contribution.

Phisical Asset Management Handbook