yield Simplistically, the term is used for the ratio of good assemblies at the end of a process to the number of assemblies originally started, expressed as a percentage. In practice, an apparently high yield can disguise the fact that substantial rework has had to be undertaken in order to rectify faults. ‘First-pass’ yield is a better monitor of the effectiveness of a process, but even here this may disguise planned intervention after processes such as wave soldering.