Parkinson’s law: why work expands to fill the time you give it
Parkinson’s law says that work expands so as to fill the time available for its completion. Give a presentation a week and it takes a week; give it an hour and you often finish in an hour. Below: where the law comes from (a satirical essay about civil servants), what research found, where it breaks down, and how to turn it to your advantage without falling into the opposite trap of impossible deadlines.
- Parkinson’s law was coined by British historian C. Northcote Parkinson in a satirical essay in The Economist on 19 November 1955.
- It began as a critique of bureaucracy: the British Admiralty’s staff kept growing while its ships and sailors shrank.
- An experiment by Bryan and Locke (1967) found that people given a looser time limit worked more slowly, because they set their own goal by the limit.
- Use it with shorter timeboxes, your own earlier deadlines and a clear definition of “done”.
- Too tight a limit runs into the planning fallacy – a good box is a little shorter than comfortable, not unrealistic.
Where Parkinson’s law comes from
Cyril Northcote Parkinson was a British naval historian. In November 1955 he published an anonymous satirical essay in The Economist that opens with: “It is a commonplace observation that work expands so as to fill the time available for its completion.”
His example is an elderly lady with a whole day to send a postcard to her niece: an hour finding the postcard, another hunting for her glasses, half an hour searching for the address, an hour and a quarter writing and twenty minutes deciding whether to take an umbrella to the postbox. What a busy person would do in three minutes takes her the entire day – and leaves her exhausted.
The real target was bureaucracy. Parkinson argued that the number of officials grows regardless of the amount of work, because an official wants to multiply subordinates, not rivals, and officials make work for each other. He backed it with Admiralty figures: between 1914 and 1928 the number of capital ships fell by about two thirds and officers and men by about a third, while Admiralty officials grew by roughly 78%. He later expanded the essay into the book Parkinson’s Law (1957).
What research says
Parkinson wrote satire, not science, but psychologists later tested the idea. In an experiment by James Bryan and Edwin Locke (1967), participants did the same tasks under time limits of different sizes. Those with more time worked more slowly – and not out of laziness. The authors showed that people set their own pace and goal from the time available: “I have an hour for this” quietly becomes “I’ll do this in an hour”.
The practical takeaway: Parkinson’s law is not a law of nature but a result of the goal you (often unconsciously) set. Change the goal and the time changes too.
The law of triviality
The same book describes another much-quoted observation: a committee approves a nuclear reactor in minutes because nobody understands it, then argues for an hour about a bike shed because everyone has an opinion. Time spent on an agenda item is often inversely proportional to its importance. If that sounds like your meetings, the Eisenhower Matrix helps.
Where Parkinson’s law shows up
- Distant deadlines. A project gets “thought through” for two weeks and done in the last two days. It isn’t only procrastination – while the deadline feels far away, the work expands into thinking and polishing.
- Tasks with no definition of done. “Improve the website” has no end, so it consumes whatever time you give it.
- A completely free day. A day without a single fixed point often ends with the feeling nothing got done. A day with two meetings is often, paradoxically, more productive.
- Email and chat. Without a set time for them, they fill every gap in the day.
- Perfectionism. The last few percent of quality can be polished forever – and without a limit, they will be.
5 ways to make Parkinson’s law work for you
- Timebox. Give a task a fixed block – 25, 50 or 90 minutes – and when it ends, decide whether that’s enough or it needs another block. The Pomodoro Technique and the free online Pomodoro timer teach exactly that.
- Set your own earlier deadline. Client deadline on Friday? Make yours Wednesday. You keep the buffer, but the work doesn’t spread over the whole week.
- Define “done”. Instead of “improve the website”, write “rewrite the intro and replace three photos”. A concrete end stops the work.
- Batch small tasks. Email and admin get one or two blocks a day, not the whole day – see time blocking.
- Less time for less important work. Important tasks get your best hours, everything else a shorter limit. Parkinson then works for you: small tasks shrink into the time left for them.
Where it fails: the trap of too-short deadlines
Parkinson’s law has a mirror image: the planning fallacy. People consistently underestimate how long tasks take. Cut a limit too far and the work won’t fit, quality drops and stress rises.
- A box should be a little shorter than comfortable, not half of a realistic estimate.
- Creative and new work needs time to warm up and to make mistakes; a short limit there tends to hurt.
- Don’t plan the whole day tight. Short boxes for single tasks plus a buffer in the day plan is the combination that works.
Parkinson’s law in CORTEX
In CORTEX (free for everyone) you get tools for both sides – shorter boxes and a buffer:
- Focus as a timebox. Start it on a task as a Pomodoro (25/5, 50/10, 90/15 or a custom length) or free-running. Time is logged automatically, so you see how long the task really took.
- An estimate on every task. Quick capture understands durations: “Prepare documents for the accountant ~45m”. If a timer runs past twice the estimate, CORTEX asks “Still working?” and offers to trim the extra time.
- Plan my day with a buffer. The day planner fits tasks into the day’s capacity and keeps part of it free, so short boxes don’t turn into a planning fallacy.
Frequently asked questions
What does Parkinson’s law say?
That work expands so as to fill the time available for its completion. C. Northcote Parkinson wrote it in an essay in The Economist in 1955.
Is Parkinson’s law scientifically proven?
It started as satire about bureaucracy, not research. But a 1967 experiment by Bryan and Locke showed that people with a looser time limit work more slowly, because they set their own pace and goal from the limit.
How can I use Parkinson’s law?
Give tasks fixed timeboxes a little shorter than comfortable, set your own earlier deadline, define what done means and batch small tasks like email into one or two blocks a day.
What is the difference between Parkinson’s law and the planning fallacy?
Parkinson’s law says work fills all the time you give it. The planning fallacy is the opposite error: we give a task less time than it needs. A good plan combines shorter boxes for tasks with a buffer for the whole day.
What is Parkinson’s law of triviality?
An observation from the same book: a group spends the most time on things everyone understands (like a bike shed) and the least on the truly important, complex ones.
Sources and further reading
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