Not all programmers are created equal

Data measuring individual programmer performance was gathered over a 12-year period in a stable work group responsible for developing and supporting a single 4.2-million-line operating system and associated program products, communication systems, and databases. Analysis shows a wide variation in productivity from best- to poorest-performing individuals and groups. Eight percent of the work result was done by a single programmer out of a workforce of almost 200. A variation of 200:1 separated the top programmer from the poorest performers. The top 27% of programmers did 78% of the work. Planning for average productivity can therefore result in significant errors in projects