Yield is a quality ratio. It is calculated by dividing the number of good pieces of work by the number of pieces of work started and is expressed as a percent. If a process starts work on 100 items, for example, and 92 make it off the end of the assembly line, the yield is 92%.

Scrap or other losses account for the drop in yield. This may include production mistakes, poor components, failed tests, or any other situation that prevents completion of a good unit.

Yield can be a bit misleading, though, as rework often occurs within a process. For that reason, first pass yield / FPY (or rolled through yield) is often a better metric.