Productivity guides

The articles fall into three groups. One piece stands apart from them: the overview, which walks the whole field in one sitting, from planning and attention through to sleep and energy, and marks which parts survive contact with the evidence. It is the one to read if you are only going to read one, and it points at the rest.

Five articles deal with timed work blocks. The first sets out the original method and how to run a session without inventing rules that were never in it. The second asks how long a block ought to be and is honest that the evidence thins out to a single trial and a lot of confident assertion. The third compares the two most quoted intervals and traces where the second one actually came from, which is not a laboratory. The fourth is about revision, reading and problem sets, where the material decides the interval rather than the other way round. The fifth is about ADHD, and keeps a clear line between what an external timer plausibly does and what anyone has tested.

Three more are about planning rather than concentrating. The time-blocking article is written for an engineering week, where the interruptions are structural rather than a personal failing. The estimation article works through the planning fallacy and the countermeasures that survive it, and it is the one to read before you start filling in the estimate field on the task manager. The weekly review article takes the vaguest step in GTD and turns it into something you can finish in one sitting.

The last two deal with what stops people rather than with what they should do. One treats procrastination as a problem of mood rather than of discipline, which is what the research supports and why the usual advice slides off. The other gives the ceiling: how much genuinely focused work a day is realistic, how to measure your own number instead of borrowing someone else's, and what the remaining hours are good for.

Each article ends by pointing at the tools it describes, and most of them are worth reading in the opposite order to the one you would expect: start with the tool, and come back to the guide at the point where the tool stops helping. The timer that keeps being abandoned at minute eleven is a question about interval length; the task list whose estimates are always half of what the work takes is a question about estimation; the week that disappears without a trace is a question about reviews.

The articles are long by design and none of them is a checklist. Every one carries the author's name, the day it went up and, where it has changed since, the day it last changed, with that second date taken from the repository's own history rather than typed in by hand. Nothing is held back behind a sign-up, and there is no newsletter waiting at the end of an article.

Each guide starts from the primary sources rather than from other productivity writing. When a claim rests on a study, the article names it, says how many people took part and under what conditions, and says plainly when the result is correlational, comes from a single trial, or has never been replicated. When a widely repeated claim turns out to have no study behind it at all, that gets stated as well.

Three examples run through these pages. The 25-minute Pomodoro was an arbitrary choice: Francesco Cirillo settled on it as a student after trying intervals somewhere between 5 and 30 minutes, and kept it because it worked for him. The claim that refocusing after an interruption takes 23 minutes and 15 seconds appears in none of Gloria Mark's published papers; the precise-sounding figure circulates through interviews and secondary writing rather than any study, and the measured figure, about 10 to 15 minutes to get back to focused work, belongs to a different paper, Iqbal and Horvitz (2007). Ego depletion, the model that treats willpower as a reserve running down through the day, failed two large multi-lab replications, a 23-lab effort in 2016 and a 36-lab one in 2021, with effects indistinguishable from zero.

If you think something here is wrong, send a source to contact@chronoclock.app. A link to the paper, the original interview or the page a number came from is far more useful than a correction on its own, and it is what gets a claim checked quickly. Guides are edited in place when the evidence moves or a mistake is found, rather than left standing as they were first published.