Hofstadter's law

Hofstadter's law is a self-referential adage, coined by Douglas Hofstadter in his book Gödel, Escher, Bach: An Eternal Golden Braid (1979) to describe the widely experienced difficulty of accurately estimating the time it will take to complete tasks of substantial complexity:^[1]^[2]

Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law.^[2]

The law is often cited by programmers in discussions of techniques to improve productivity, such as The Mythical Man-Month or extreme programming.^[3]

^ Waters, Donald J.; Commission on Preservation and Access (1992). Electronic technologies and preservation. Commission on Preservation and Access. ISBN 9781887334167. Retrieved 2011-06-08.
^ ^a ^b Gödel, Escher, Bach: An Eternal Golden Braid. 20th anniversary ed., 1999, p. 152. ISBN 0-465-02656-7.
^ David M. Goldschmidt (October 3, 1983). "The trials and tribulations of a cottage industrialist". InfoWorld. 5 (40). InfoWorld Media Group, Inc.: 16. Retrieved 2011-06-08.