BROOKS’S LAW Adding manpower to a late software project makes it later.

GRESHAM’S LAW “Bad money drives good money out of circulation.” If coins of the same legal tender contain metal of different value, the coins composed of the cheaper metal will be used for payment, and those made of more expensive metal will be hoarded and disappear from circulation. Named after Sir Thomas Gresham, a British financier and founder of the Royal Exchange.

PARETO PRINCIPLE Also known as the 80/20 rule and named after Vilfredo Pareto (1848–1923), an Italian economist, who determined that 80% of activity comes from 20% of the people. The principle was extended (or simply misunderstood) by Joseph Juran, an American management guru, who suggested that for many phenomena 80% of consequences stem from 20% of the causes. That is, in many instances a large number of results stem from a small number of causes, eg, 80% of problems come from 20% of the equipment or workforce.