The 41% to-do stat and the 23-minute rule, checked

Do 41% of to-do items never get done? Does it take 23 minutes to refocus after an interruption? Both numbers come from real sources, but neither one measured what people use it to say. Below is what each source actually found, and the smaller research results that do hold up.

If you make a to-do app, these two numbers are tempting. Both would look good on our home page. We read the sources instead, and decided not to use either one.

Do 41% of to-do items never get done?

Where it comes from. It’s on page 7 of The Busy Person’s Guide to the Done List, a guide published by the software company iDoneThis. The guide carries a 2014 copyright, and the figure comes from the company’s own app data.

What was measured. The guide doesn’t say. It gives no number of users, no number of tasks, no time period and no definition of “completed.”

Think about what an unchecked item in an app can mean. The task might have been done somewhere else, dropped on purpose, entered twice, or still be open today. The guide doesn’t separate these cases.

Why we leave it out. The figure describes entries in one company’s app, but it gets repeated as if it described everyone’s tasks. Nothing in the source supports that jump. We haven’t shown the number is wrong. We just can’t stand behind it.

What about “only 15% of work gets written down”?

The same page has a second figure that gets stretched the same way: 15% of the “dones” people logged had started as to-do items. That’s sometimes retold as “only 15% of work gets written down.” The source didn’t measure all work. It measured entries in one app.

Does it take 23 minutes to refocus after an interruption?

Where it comes from. Gloria Mark, a researcher who studies interruptions at work, gave this number in an interview with Fast Company published on July 28, 2008. She said it takes an average of 23 minutes and 15 seconds to get back to the task.

What was measured. The interview doesn’t name the data behind the exact figure, and we couldn’t find it. We checked two papers by Mark and her colleagues, and neither one says 23:15.

• The 2008 paper is an experiment with 48 participants doing a simulated office email task. People finished interrupted tasks in less time, with no drop in quality, but with more stress.
• The 2005 paper is a field study of 24 information workers at one company. Interrupted work was picked back up after 25 minutes and 26 seconds on average. People worked on about two other things in between, and 77% of interrupted work was resumed the same day.

So the 2005 figure is the time until someone returned to a task, and they were doing other work in the meantime. It isn’t time spent unable to concentrate. The spread is also wide: the standard deviation is nearly 55 minutes, more than twice the average.

Why we leave it out. “Every interruption costs you 23 minutes of focus” isn’t what was measured. People then multiply it by the number of notifications in a day and report hours lost. No source supports that math.

What does research on to-do lists and reminders show?

These studies didn’t test Pippin. They used other tools, other people and other tasks. But they’re solid, and they point in a clear direction.

Reminders help people follow through. In four online experiments with 1,196 participants in total, setting external reminders improved how well people carried out things they meant to do later.

Effort decides whether people set reminders at all. In two preregistered experiments with 52 adults each, researchers made setting a reminder take a bit more effort. People set fewer reminders when it did.

A specific plan can quiet an unfinished goal. In a 2011 paper, people who made a plan for how, when and where they would reach a goal were less distracted by it. Writing a task down in a concrete way seems to take some weight off your mind.

What this means for a to-do list

Put the first two results together. Reminders help, and people skip them when they take effort. A to-do list that asks you to type in, update and check off every task is a lot of effort, every day. That’s the cost Pippin is built to remove.

Pippin is a Mac app that reads the text on your screen and keeps your to-do list for you. It adds tasks as they come up, updates them as the work moves, and checks them off when they’re done. You get the benefit of a written list without the upkeep that makes people drop one.

We describe how that upkeep wears a list down in why you can’t keep a to-do list past a busy week, and what it’s made of in keeping a to-do list up to date is the real work. The FAQs on the home page cover the rest.