Parkinson's law can refer to either of two observations, published in 1955 by the naval historian C. Northcote Parkinson as an essay in The Economist:[1]
The first paragraph of the essay mentioned the first meaning above as a "commonplace observation", and the rest of the essay was devoted to the latter observation, terming it "Parkinson's Law".
The first-referenced meaning of the law – "Work expands to fill the available time" – has sprouted several corollaries, the best known being the Stock-Sanford corollary to Parkinson's law:
If you wait until the last minute, it only takes a minute to do.[2]
Other corollaries include Horstman's corollary to Parkinson's law, coined by Mark Horstman of website manager-tools.com:[3]
Work contracts to fit in the time we give it.[4]
the Asimov corollary to Parkinson's law:
In ten hours a day you have time to fall twice as far behind your commitments as in five hours a day.[5]
as well as corollaries relating to computers, such as:
Data expands to fill the space available for storage.[6]
The law can be generalized further as:
The demand upon a resource tends to expand to match the supply of the resource (If the price is zero).
An extension is often added:
The reverse is not true.
This generalization has come to resemble what some economists regard as the law of demand – namely, the lower the price of a service or commodity, the greater the quantity demanded. This is also referred to as induced demand.
This was the main focus of the essay by Cyril Northcote Parkinson, published in The Economist in 1955,[1][7] and reprinted with other similar essays in the successful 1958 book Parkinson's Law: The Pursuit of Progress.[8] The book was translated into many languages. It was highly popular in the Soviet Union and its sphere of influence.[9] In 1986, Alessandro Natta complained about the swelling bureaucracy in Italy. Mikhail Gorbachev responded that "Parkinson's law works everywhere."[10]
Parkinson derived the dictum from his extensive experience in the British Civil Service. He gave, as examples, the growth in the size of the British Admiralty and Colonial Office even though the numbers of their ships and colonies were declining.
Much of the essay is dedicated to a summary of purportedly scientific observations supporting the law, such as the increase in the number of employees at the Colonial Office while the British Empire declined (he showed that it had its greatest number of staff when it was folded into the Foreign Office due to a lack of colonies to administer). He explained this growth using two forces: (1) "An official wants to multiply subordinates, not rivals", and (2) "Officials make work for each other." He noted that the number employed in a bureaucracy rose by 5–7% per year "irrespective of any variation in the amount of work (if any) to be done".
Parkinson presented the growth as a mathematical equation describing the rate at which bureaucracies expand over time, with the formula , in which k was the number of officials wanting subordinates, m was the hours they spent writing minutes to each other.
Observing that the promotion of employees necessitated the hiring of subordinates, and that time used answering minutes requires more work; Parkinson states: "In any public administrative department not actually at war the staff increase may be expected to follow this formula" (for a given year) [1]
In a different essay included in the book, Parkinson proposed a rule about the efficiency of administrative councils. He defined a "coefficient of inefficiency" with the number of members as the main determining variable. This is a semi-humorous attempt to define the size at which a committee or other decision-making body becomes completely inefficient.
In Parkinson's Law: The Pursuit of Progress, London: John Murray, 1958 a chapter is devoted to the basic question of what he called comitology: how committees, government cabinets, and other such bodies are created and eventually grow irrelevant (or are initially designed as such). (The word comitology has recently been independently invented by the European Union for a different non-humorous meaning.)[11][12]
Empirical evidence is drawn from historical and contemporary government cabinets. Most often, the minimal size of a state's most powerful and prestigious body is five members. From English history, Parkinson notes a number of bodies that lost power as they grew:
A detailed mathematical expression is proposed by Parkinson for the coefficient of inefficiency, featuring many possible influences. In 2008, an attempt was made to empirically verify the proposed model.[13] Parkinson's conjecture that membership exceeding a number "between 19.9 and 22.4" makes a committee manifestly inefficient seems well justified by the evidence proposed[citation needed]. Less certain is the optimal number of members, which must lie between three (a logical minimum) and 20. (Within a group of 20, individual discussions may occur, diluting the power of the leader.) That it may be eight seems arguable but is not supported by observation: no contemporary government in Parkinson's data set had eight members, and only king Charles I of England had a Committee of State of that size.
It is often argued – as now e.g. in the discussion of the future size of the European Commission – that decision making bodies of a size beyond 20 become strongly inefficient. We report empirical evidence that the performance of national governments declines with increasing membership and undergoes a qualitative change in behavior at a particular group size. We use recent UNDP, World Bank and CIA data on overall government efficacy, i.e. stability, the quality of policy formulation as well as human development indices of individual countries and relate it to the country's cabinet size. We are able to understand our findings through a simple physical model of opinion dynamics in groups..
