Why checklists work comes down to one thing: they catch the routine steps that skilled people skip when they are rushed or interrupted, and they teach nothing new. That is also their limit, because a list prevents expensive mistakes only when people stop at a set moment and actually use it. A 19-item surgical checklist was linked to fewer deaths in a 2009 study at eight hospitals in eight countries, yet surgical checklists brought no measurable change after Ontario encouraged every hospital to adopt one.¹²

For your own work, the research and the guidance built on it come down to four moves, each explained further down:

1. Pick one pause point where a miss is expensive.
2. List only the items that are easy to miss.
3. Decide between read-do and do-confirm, that is, whether the list leads the work or checks it afterward.
4. Try it on real work, then revise it.

This page stays with one tool. For where it sits among GTD, kanban and the other named methods, read how the best-known productivity methods compare.

Why checklists work: memory drops the easy steps

Checklists work because expert memory is dependable for the hard parts of a job and patchy for the routine ones. The US Army Air Corps drew that conclusion from a bomber crash in 1935, and a 1990 report for NASA described the same weakness in airline cockpits more than fifty years later.

In October 1935, Boeing’s Model 299, the prototype of the bomber later called the B-17, took off from Wright Field in Ohio, pitched up, stalled and crashed. An Army board found that its elevator control had been left locked, and judged that no pilot was likely to notice in time. The crew was very experienced, led by a seasoned test pilot, and checking that the controls moved freely was an ordinary precaution. The Air Corps concluded that the weak point was human memory, not the aircraft, and gave crews checklists for each phase of flight.³

The mechanism is familiar from any skilled work. Steps you have done a hundred times run on autopilot, and autopilot is exactly what an interruption breaks. In a 1990 NASA report, Asaf Degani and Earl Wiener described how distractions break a checklist’s sequence, leaving the pilot to remember where the list stopped and which items were done. They also saw crews speed through lists by calling several items at once and answering in one chunk, which leans on memory, the very thing the list exists to back up.⁴

Think of sending a quarterly report to a client. You know how to write it. What goes wrong is the attachment left off, last quarter’s figure not updated, or the wrong person copied, usually on a busy afternoon after a phone call. None of those is a knowledge problem. Each is a known step dropped at a moment of pressure, and that is the kind of error a checklist is built to catch.

A checklist is NOT a teaching tool or an algorithm

So give a checklist only the steps you could do half asleep and might still skip, and keep the explaining for training notes or a manual.

What the WHO surgical checklist changed in eight hospitals

The best-known early evidence for checklists came from surgery. In a 2009 study led by Alex Haynes within the World Health Organization’s Safe Surgery Saves Lives program, eight hospitals from Toronto to Ifakara, Tanzania, introduced a surgical safety checklist, and deaths and complications after surgery fell compared with the months before.¹

The study

Moderate evidence

Eight hospitals, eight countries, one checklist: Safe Surgery Saves Lives, 2009

Researchers recorded outcomes for consecutive patients aged 16 and over before and after the checklist arrived. Deaths in hospital within 30 days of the operation fell from 1.5 percent to 0.8 percent, about 15 in 1,000 patients to 8 in 1,000, and complications fell from 11.0 percent to 7.0 percent.¹

The drop was large, and the design limits what it can prove. Without a randomized comparison group, some of the gain could come from teams knowing they were being watched or from other changes in those months. The authors write that the checklist was designed to improve team communication and consistency of care, so it was meant to do more than jog one person’s memory. We worked from the study’s abstract alone.¹ Atul Gawande, one of its authors, later wrote about checklists for general readers in The Checklist Manifesto.⁶

A well-known result from intensive care fits the same pattern. In a 2006 study of more than a hundred intensive care units, mostly in Michigan, a program to prevent bloodstream infections from central lines, the tubes placed in a large vein, was followed by infection rates falling by up to two-thirds.⁷ It had no comparison group either, and we saw only its abstract.

What a surgical checklist looks like in practice is a pause. The whole team stops at three moments: before anesthesia, before the first cut and before the patient leaves the operating room.⁸ Your version might be the minute before you send a contract or start a data migration. A small agency could do it before a campaign goes live: one person reads the items aloud, and anyone who sees a gap can say “not yet”. Tie your checklist to a moment that already exists in the work, so running it costs seconds, not a new meeting.

Why surgical checklists made no measurable difference in Ontario

Hanging a checklist on the wall and using it are different things. When Ontario, Canada, adopted surgical checklists through a province-wide policy, David Urbach and colleagues compared outcomes in the three months before and after each hospital’s adoption, across 101 hospitals. Death and complication rates barely moved, and the small differences were not statistically significant.²

The study, funded by the Canadian Institutes of Health Research, is the clearest test we found of checklists spreading by policy across typical hospitals. We read only its abstract, which reports nothing on how thoroughly teams used the lists, so the result cannot show that Ontario’s surgeons skipped them. It shows only that adoption by policy came with no measurable gain.²

Other research points to use as the missing piece. In a meta-analysismeta-analysis: A study that combines the results of earlier studies on the same question into one overall estimate. Pooling makes the estimate more precise, but it cannot repair the studies it pools: a meta-analysis of surveys is still survey evidence.Full entry in the glossary published in 2018 that added an international patient cohort to earlier studies, Abbott and colleagues found better outcomes where checklists were used, but they warned this could simply reflect better overall care in those hospitals.⁹ A 2025 review found that, in the studies that measured it, only about half of surgical checklists were filled in completely, and that training, management support and regular feedback went with better use.¹⁰

Armstrong and colleagues’ systematic reviewsystematic review: A review that fixes its question and its rules for including studies in advance, then searches out every study that fits and weighs them together. Some systematic reviews pool the results into a meta-analysis; others describe what the studies found without combining the numbers.Full entry in the glossary of hundreds of surgical checklist studies, published in 2022, found that most never described how the checklist was actually completed, which, its authors argue, is why it is hard to tell where it works and where it fails.¹¹ None of these studies proves that thin use explains Ontario’s result; they show that use is often thin and rarely measured. The Michigan infection program, built around a checklist of five infection-control steps, shows what real use involved. Mary Dixon-Woods and colleagues argued in 2011 that crediting its success to “a simple checklist” was a myth: units wrote their own versions, a nurse watching each line insertion could stop it if a step was skipped, and infection rates were fed back to every unit.¹²

Office teams fall into the same trap. Picture a release checklist added to a ticket template because a manager asked for one: within weeks, people tick every box in one go just before closing the ticket. The list exists, and nothing is being checked. Before you judge any checklist, find out whether it was run item by item at the moment it was meant for; a list ticked from memory is a to-do list, not a check.

Further reading

• 

  The Checklist Manifesto: How to Get Things Right

  by Atul Gawande

  Gawande, an author of the 2009 surgical study, on why skilled people skip routine steps and how to write a checklist a team will run.

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Read-do or do-confirm: two ways to run a checklist

There are two ways to run a checklist, and choosing the right one matters more than the wording of the items. Aviation research calls them challenge-response, where the crew sets things up from memory and then verifies the critical items, and do-list, where the list leads the crew step by step.⁴

1. Read-do: read one item, do it, then read the next; suited to rare, unfamiliar or urgent tasks where order matters
2. Do-confirm: do the work from memory, then pause and check every item; suited to routine work done by people who know it

A 2023 medical review in the journal Anaesthesia uses plainer names, read-do and do-confirm, and explains when each fits. Read-do suits emergencies, where actions may need to happen in order and there may be no time to recover from a missed step; do-confirm suits less urgent work, where you act first and then check for gaps. Pooling randomized trials of cognitive aids, mostly in simulated medical emergencies, the review found that teams with an aid missed far fewer care steps, from roughly four in ten to about one in ten, with moderate-quality evidence.¹³ Those were simulations with clinicians, not real offices, so treat them as proof of the principle rather than a promise for your desk.

Carried over to office work, which is our reading rather than anything the review tested, do-confirm fits the tasks you do weekly: send the report, then run the checks before it goes. Read-do fits the tasks you do once a year or in a crisis, such as closing the books, restoring a backup or handing over a project when a colleague leaves suddenly. For those, memory has had no practice, so let the list lead.

Back to the client report from the first section. Written as a do-confirm list, it is short enough to run in under a minute, and each item covers a slip that has probably happened to you before.

Evidence from knowledge work is thin. In a 2022 experiment, professional software developers were randomly assigned to review code with no aid, a checklist or a guided checklist. The authors report that the checklist supported reviewers on the more complex review, but they found no strong overall link between the aid and review performance.¹⁴ That is one study, mostly of reviewers new to code review, so treat it as a hint, not a rule.

How to build a checklist people will actually run

A checklist that people actually run is short, tied to a natural pause and revised after real use. Ariadne Labs, a center for health systems innovation, sums up the method in a one-page guide.⁵ The steps below follow that guide; they are expert advice, not tested one by one.

1. Pick one pause point where a miss is expensive

Choose a moment in the work that already exists, such as before sending, before launching or before signing, and where a skipped step costs real money, time or trust. One checklist per pause point keeps each list short.

2. List only the items that are easy to miss

Include an item only if skipping it is dangerous and nothing else catches it. Ariadne’s guide suggests fewer than 10 items per pause point and wording simple enough to read aloud.⁵ Degani and Wiener’s observation that crews take shortcuts through long, time-consuming lists is the reason to keep cutting.

3. Decide between read-do and do-confirm

Use read-do for rare, unfamiliar or urgent tasks, and do-confirm for routine ones you know well. Say which at the top of the list so nobody has to guess.

4. Try it on real work, then revise it

Run the list on the next few real cases and note which items people skip or question. Ariadne’s guide asks for trials with the people who will use the list, changes after repeated trials and a date on every version.⁵ For a team, agree that anyone may pause the work when an item is missed, which was part of what made the Michigan program work.

WiserHours

Before you rely on a new checklist

• It is tied to one pause point that already exists in the work
• Every item is easy to miss and costly if missed
• It has fewer than 10 items
• It says whether it is read-do or do-confirm
• You have tried it on real work and revised it
• It carries the date of its latest version

Find this checklist online:
https://wiserhours.com/productivity-systems/why-checklists-work/#checklist-why-checklists-work-build

The evidence behind each step, from strongest to weakest:

The bottom line

Use a checklist for the step you know well and might still skip, and expect nothing more from it. Infections fell in the Michigan program, where units wrote their own lists and a nurse could stop a procedure when a step was missed; under Ontario’s adoption policy, checklists made no measurable difference. Start with one pause point in your week where a miss is expensive, write fewer than 10 items, and run the list every time for a month before you judge it.