Parkinson's law is the tendency for the amount of work required for something to increase so that it consumes any amount of time that may be allotted to it. The concept is often generalized to refer to the tendency for any available capacity in a given system to be used.
The implication is that no matter how extensive your resources, the demands on them will grow to ensure they're depleted. Parkinson's law has implications for many areas of business, including project management, time management, resource allocation, storage capacity planning and requirements analysis.
Cyril Northcote Parkinson, a British Naval historian and author, observed that "work expands so as to fill the time available for its completion," based on his experience in the British Civil Service. Parkinson's law first appeared in a 1955 essay published in The Economist. Parkinson expanded on his principle in two books, Parkinson's Law And Other Studies in Administration and Parkinson's Law: Or The Pursuit of Progress,both published in 1957.
Here are a few examples of Parkinson's law in various contexts:
- Applications will usually consume all available bandwidth.
- The volume of data tends to grow to fill storage capacity.
- Project requirements typically increase to the extent that resources are fully used up.
- Software expands to use up system memory.
- Financial outlay will increase to exhaust any usable budget.
Horstman's corollary to Parkinson's law maintains the converse, the less commonly observed phenomenon that work contracts to fit within the time allocated for it. Another less familiar principle, Parkinson's law of triviality, refers to people's tendency to devote a large amount of time to unimportant details while essential tasks are not getting the time they require.