Week 6 Lab: Twenty-Five Minutes

29 March 20273 min readlow risk

This week

The most repeated productivity instruction in the world was one student's answer to one question, so this week we test it properly.

What you bring to the lab

The lesson below is how you get there. The lab is where you show it.

  • your two conditions differ in exactly one respect
  • the order you tried them in is balanced, and you can show how
  • you state what result would have counted as the timer losing

The technique is named after a tomato. Francesco Cirillo, a university student in the late 1980s who could not concentrate, picked up a tomato-shaped kitchen timer and bet himself he could study, really study, for ten minutes. That is the origin as his own 2006 paper tells it. The account on his site today says the question was two minutes, which is worth knowing before you trust any other detail of the story.

That is the entire provenance of the number. One person, one timer, and an interval that the paper dates to 1992 without ever comparing it against another interval. It was put online for free in 2006, and is now taught in schools, built into hundreds of applications, and recommended to you as though it were a property of human attention.

The awkward part

This week’s reading list has a hole in it, and the hole is the lesson.

We have no effect claim to offer you about twenty-five minutes. Not a weak one, not a contested one: none. There is no trial establishing that twenty-five minutes beats forty, or eighteen, or however long you happen to be able to concentrate today. The interval is not disputed in the literature so much as absent from it.

Cirillo, to his credit, has never claimed otherwise. His own paper describes twenty-five as what worked for him and then recommends thirty in its results section, which is a stronger admission than most of his readers have ever made. The overreach happened downstream, in everyone who repeated the number without reading the document it came from.

So we test it

You will compare two work-block lengths. Twenty-five minutes against something else: your own guess, forty minutes, whatever you suspect might suit you better. One variable, two conditions.

The difficulty is order. If you run twenty-five minutes all week and forty the week after, then “the second one was better” and “I got better at this” are the same sentence, and you cannot tell them apart. Counterbalancing is the fix: you alternate, so that being second happens equally often to both conditions. It is a small administrative discipline that buys you a real comparison.

Before you start, you will write down what you expect, how you will measure it, and what result would make you conclude the timer had lost. That document is a pre-registration, and handing it in before you collect anything is the first assessed piece of work in this course. It exists because the alternative is deciding what you were testing after you have seen how it went, which is how you end up with a technique that works for everyone and evidence for no one.

What to bring

Your week 5 record, because we are reusing the discipline you built there. A guess about your own best interval, written down, so you cannot revise it afterwards. And a timer that is not on your phone, if you can find one, not for any measured reason, but because Cirillo’s wasn’t, and it is worth noticing how different the same instruction feels when it cannot also show you a notification.

Evidence on file

48 people not blinded

Interrupted every two minutes, people finished the task in less time with no loss of quality, and reported significantly more stress, frustration and effort. Conditions were counterbalanced, which is this week's method.

Mark G, Gudith D, Klocke U, The cost of interrupted work, CHI 2008, pages 107-110
History, not measured

The interval began as one student's bet with himself in the late 1980s, using a tomato-shaped kitchen timer. The paper dates the method to 1992 and describes no trial of any interval length against any other.

Francesco Cirillo, The Pomodoro Technique, free paper released 19 October 2006, version 1.3 of 15 June 2007, preface and section 1

The only sweep of interval lengths in that paper was run by work groups Cirillo was mentoring, not on himself. They went from an hour to two hours, down to forty-five minutes, then ten, and settled on thirty. The same paper's results section recommends thirty minutes, not twenty-five.

Francesco Cirillo, The Pomodoro Technique, section 3.2, The Length of the Pomodoro

The paper's one appeal to outside evidence about interval length, that twenty to forty-five minute intervals maximise attention, footnotes a Teach Yourself Literature Guide to Orwell's Animal Farm.

Francesco Cirillo, The Pomodoro Technique, bibliography reference 15, citing Iona McGregor with Tony Buzan, A Guide to Animal Farm, Hodder and Stoughton, 1998, ISBN 0-340-66401-0

Teaching team