Parkinson's Law was a joke about the Admiralty, and the best-known deadline study behind it has been retracted

In 1914 the British Admiralty employed 2,000 officials in Whitehall to run a navy of 62 capital ships and 146,000 officers and men. By 1928 the fleet had shrunk to 20 capital ships and 100,000 men, and the officials numbered 3,569. A history professor in Singapore, C. Northcote Parkinson, put these figures in a table for The Economist in November 1955, noted a rise of 78.45 percent, and declared that he had discovered a law.

The short version of that law is “work expands so as to fill the time available for its completion”. It began as satire about bureaucracy, and most of the experimental support people attach to it comes from a deadline study that Psychological Science retracted on 2 September 2026. What survives is smaller: a plausible habit of mind, a thin set of experiments, and a better question about who sets the deadline.

What did Parkinson actually claim in 1955?

The sentence everyone quotes is the first line of the essay, and he introduces it as “a commonplace observation”. He was not claiming it as the discovery. The illustration is an elderly lady of leisure who spends a whole day on a postcard to her niece at Bognor Regis: an hour finding the card, another hunting for spectacles, half an hour on the address, an hour and a quarter composing, and twenty minutes deciding whether to take an umbrella to the pillar-box in the next street. A busy man, he says, would be done in three minutes.

The discovery proper is about headcount. Parkinson argued that the number of officials and the amount of work “are not related to each other at all”, and that staff would grow at much the same rate whether the work increased, diminished or disappeared. His two engines were that an official wants subordinates, not rivals, and that officials make work for each other. The Admiralty table was his proof, and the Colonial Office was the sequel: 372 officials in 1935, 450 in 1939, 817 in 1943, 1,139 in 1947 and 1,661 in 1954, over years when the empire was handing back its territories. He computed peacetime growth of 5.24 and 6.55 percent a year, averaged them to 5.89, and then produced a formula that predicted an increase “between 5.17 percent and 6.56 percent” whatever the workload.

It is a very good joke, delivered with a straight face and a mock-algebraic formula. He closed by calling the law “a purely scientific discovery” that is “inapplicable except in theory to the politics of the day”, which was the wink.

How did a joke about civil servants become a rule about your to-do list?

By being quotable. “Work expands to fill the time” travels without the footnotes, and a postcard that eats a day is more relatable than a Colonial Office table. The first line detached from the essay and went into planners and productivity books; the time-boxing advice in our piece on manufactured urgency leans on it too.

There is some experimental support, though it is narrower than the slogan. In 1999 Laura Brannon, Paul Hershberger and Timothy Brock reported in Psychonomic Bulletin & Review that people slowed their work on one task when they learned the following task had been cancelled. That is the principle at the scale of one afternoon, in undergraduates judging photographs. It shows a task stretching when stretching is free. It does not show that a tighter deadline produces better output.

What happened to the famous self-imposed deadline study?

Most popular accounts of deadline psychology rest on Dan Ariely and Klaus Wertenbroch’s 2002 Psychological Science paper, which reported that people will set costly deadlines for themselves, and that evenly spaced external deadlines beat self-set ones. Its second study had 60 students proofreading under weekly, end-of-term or self-chosen deadlines.

Hyndman and Bisin ran a pre-registered replication of that proofreading study and reported that changes in the deadlines had a negligible effect on the performance measures. The Data Colada researchers (Simonsohn, Nelson and Simmons) then published analyses on 31 August and 2 September 2026 concluding that the study’s data were “severely tampered with or fabricated”. Wertenbroch had asked the journal on 23 July to retract the paper, saying the forensic evidence showed that much or all of the data were false. Ariely said in a statement that the data “cannot be trusted”. The retraction notice is dated 2 September.

This is untidy. Ariely said earlier, on 7 August, that the records available to him could not answer the questions raised, and a retraction removes one paper, not the idea. But the specific claim that self-imposed deadlines are weaker than evenly spaced external ones has lost its best-known evidence, and anything citing it, including some earlier posts here, needs that caveat.

Does any good evidence on deadlines remain?

Some does. Bisin and Hyndman’s own field experiment, published in Games and Economic Behavior in 2020, found that students asked for self-imposed deadlines, which is real information about how they see themselves. It also found that the deadlines did not raise completion rates, and that present-biased students procrastinated on single tasks while managing better when tasks repeated. A deadline you give yourself is a request for help that often goes unanswered, since the person who set it is the person who can move it.

Where that leaves us is two inferences, and they are inferences rather than findings. First, the length of the window probably matters less than whether anything happens at the end of it. Second, whoever owns the deadline matters, because a deadline its owner can quietly renegotiate behaves like no deadline.

Where does an alarm clock fit in?

An alarm is a deadline for the first task of the day. Parkinson’s elderly lady is the morning in miniature: ten minutes finding the phone, five on the weather, twenty deciding whether to get up, and a snooze button supplying a free extension each time. The window is elastic because nothing is due when it closes. Any wake-up routine that works has to make the first deadline cost something, which is the point behind the Hofstadter and Goldratt material on why padded plans get spent.

DontSnooze is a crude application of this. The alarm starts a thirty-second clock to film yourself upright, and when the clock runs out a random photo from your camera roll goes to friends. It is not magic and it governs one task, the first. Nothing here shows that thirty seconds of compliance carries into the rest of the morning, and a motivated person can still film themselves lying down. What the arrangement does supply is a deadline owned by someone else, with an end-of-window consequence that arrives on its own, and ownership is the trait the surviving research gives us reason to care about. We covered why that kind of proof is hard to fake in the piece on video proof versus self-report.

It also does nothing for the next trap Parkinson wrote about, which is the one where you polish the playlist instead of the reactor. That is the subject of the post on bikeshedding and productivity apps.

What would I take away from the Admiralty?

The numbers are real, the satire is real, and the generalisation to personal productivity is a loan against a reputation. If you want a deadline to bite, give it an owner who is not you and an event that happens when it passes. The elderly lady, one assumes, still took the umbrella. If your elastic bit is the first thirty seconds of the day, DontSnooze is one way to put a clock on it.