First time through yield - FTT
First time through yield or FTT as it may sometimes be referred to is a measure of production efficiency, ability/skill, and quality. It measures how many goods are produced correctly without flaws or re-work as percentage of total units produced in a production process or value stream.
This concept can also be easily applied to the service industry as a measure of service or orders delivered satisfactorily to customers the first time without any amendments, re-work, or complaints.
The formula to calculate FTT is: (Units produced-defective units)/units produced
The definition of defective units includes all units of production which are scrapped, re-worked, do not meet standards, require repair, or are not saleable.
The first time through yield will help you identify efficiency and changes in performance in the production process and should be used as a signal to perform further analysis and improvements if it exhibits sudden big changes.