The Efficiency Factor (EF) is an absolute measure of how productive a pairing is from the vantage point of pairing credit for time spent on the pairing. The higher the EF the more productive the pairing. Mathematically, the EF is the credit time divided by the pairing time multiplied by 1000. Pairing time is the time away from base plus one hour (to account for report time). The EF is a measure of the percentage of time you are paid while committed to the pairing. A higher PF means that you are compensated in flight pay for a higher percentage of your time on the pairing. When you check "Efficiency Factor", the highest and lowest FF values in the processed pairings are displayed on the right.