The Wonders of Checklists

A simple checklist prevents deaths after surgery, a large new study suggests

Washington Post, April 18, 2017

The Washington Post reports that a recent South Carolina study examining 30-day post-surgical mortality rate of hospitals found a reduction in deaths for those hospitals participating in a voluntary checklist-based quality improvement program, over those hospitals that were not. The study is to be published in August 2017.

I find checklists fascinating – especially when used as tools in technically demanding fields such as aviation and medicine. They are an incredibly cheap, easy-to-use and low-tech solution in fields of ever-expanding technical complexity. Yet they do have limitations, and they have taken an inordinate amount of time to be fully-embraced by hospital personnel.

For followers and practitioners of patient safety and health quality, the study’s conclusion comes as no surprise, but it does raise questions. In today’s post, I’d like to examine the history and benefits of checklist adoption. Subsequent posts will consider the limitations of checklists, the dissemination of ideas, and the implications of checklists for regulatory effectiveness – the theme of this blog.

A Brief History of the Checklist

Anyone who has ever gone grocery shopping, planned a vacation, or organized a wedding intuitively understands the value of a checklist as a memory tool.

When used for more complicated and complex endeavours, though, a checklist can be much more than a memory aid. It is a powerful tool to facilitate interdisciplinary communication, which is actually one of the most effective ways to save lives in safety-critical fields. On the other hand, checklists are not a panacea, and they do have limitations.

In the early years of aviation, pilots relied on their memory to complete the tasks of takeoff, cruising and landing. As aircraft became more complicated, the inadequacy of pilot memory alone became clear. In 1935, during a flight competition of new bombers held by the U.S. military, an experienced cockpit team was to demonstrate the new four-engine Boeing Model 299 (aka the B-17 Flying Fortress), which was considerably more technologically complex than its predecessors. Unfortunately, during pre-takeoff preparation, the pilot forgot to unlock the elevator and rudder controls. The plane stalled at takeoff and crashed, killing both pilots.

The problem was that the new flying machines had become too complicated for pilots to be able to commit each and every task to memory. Following the accident, it was argued that pilots needed more training, even though the 299’s crew was experienced and well trained. The military resisted the call for more training and instead instituted a simple checklist system to cover the tasks involved with takeoff, cruising, pre- and post-landing, priming guns, bombing, etc.

The checklists worked. Following adoption, the U.S. military flew more than 100,000 accident-free non-combat hours, and the B-17 became the mainstay for the U.S. Air Force’s European operations in World War II.[1] Checklists were subsequently adopted in the space flight and civil aviation world, and over the next several decades, the number of checklists expanded to cover every aspect and most contingencies of flight.

The journey from the Model 299 crash to the current state of strong aviation safety was not a completely smooth one. There were problems with checklists, both in their design and their application. For example, the National Transportation Safety Board (NTSB) cited misuse and nonuse of cockpit checklists in a number of air accidents in the late 1980s and early 1990s. A 1993 field study[2] found that human factors[3] had not been considered in creating checklists. The authors reviewed checklist design and use, and finding several limitations, suggested a number of design guidelines to revise form and usage.

Aviation checklists continue to be a work in progress. In the mid-1990s, Boeing found its checklists to be too long and complex, resulting in misuse, and undertook a fundamental re-design, again taking closer account of human factors.

And indeed, flying is now safer than ever.

Hospital Checklists and the Patient Safety/Health Quality Movement

Incredibly, it took more than half a century from the time that aviation began experimenting with checklists for the medical community to consider their usage.

Atul Gawande is a surgeon, academic, author and expert in patient safety and health quality. In 2007, he penned a piece for the New Yorker magazine called “The Checklist”,[4] in which he describes several initiatives headed by Dr. Peter Pronovost, of Johns Hopkins Hospital, to use checklists in intensive care units (ICUs). The results were astonishing: infections following central line insertions dropped to near-zero with checklist usage. As noted by Gawande, there is no shortage of expertise in medicine. Physicians who specialize beyond family medicine are often in their mid-30s, having completed a long residency and one or more fellowships, before entering independent practice. Even so, patients are often unintentionally harmed by medical care. For example, ICU patients often require central lines (catheters inserted through smaller peripheral veins to a central vein) for the administration of medications, nutrients and fluids. Infection was long considered a “normal” complication of central line insertion, affecting approximately 4% patients receiving them, often with terrible consequences for the patient, including death.

Dr. Pronovost decided to pilot an ICU checklist for central lines in 2001 at Johns Hopkins Hospital. He simply created a list of the five basic and well-known steps for inserting a line. He asked nurses to observe doctors for a month for their adherence to the five steps. In more than a third of patients, at least one step was missed. Nurses were given authorization to stop physicians who were missing a step, and to ask daily about whether a line should be removed. The trials showed astounding results. According to Gawande,

Pronovost and his colleagues monitored what happened for a year afterward. The results were so dramatic that they weren’t sure whether to believe them: the ten-day line-infection rate went from eleven per cent to zero. So they followed patients for fifteen more months. Only two line infections occurred during the entire period. They calculated that, in this one hospital, the checklist had prevented forty-three infections and eight deaths, and saved two million dollars in costs.

Later trials in Michigan resulted in a three-month reduction of 66 percent in post-line insertion infections, which in turn reduced the quarterly infection rate to zero, and over 18 months may have saved 1,500 lives and $100 million in what would otherwise have been infection treatment. These numbers are astonishing.

Gawande subsequently headed a worldwide surgical checklist pilot for the World Health Organization (WHO), an experience he recounted in his excellent book, The Checklist Manifesto: How to Get Things Right[5]. In eight hospitals (four in the developing world, four in the developed world, including Toronto General Hospital), teams worked to pilot and refine pre-operative, peri-operative and post-operative checklists. Again, the results were impressive. Thirty-day post-operative complications fell by an average of 37 percent (and they fell in all hospitals), and re-admission rates also fell.

The Benefits of Checklists

Pronovost found two benefits of checklists. First – they served as a memory aid. It is not necessarily lack of caring or competence that leads to a missed step in a medical procedure. As Gawande notes, it can be difficult to remember to keep the head of the patient’s in the correct position when dealing with a more dramatic event, such as a seizure. Second – checklists prescribe the minimum necessary steps for a procedure. As Pronovost found, it was surprising how frequently experienced medical personnel did not grasp the importance of certain precautions. There is so much medical knowledge available now, it is simply impossible for any one person to retain even it in their memory.

Introduction of the surgical checklist in the WHO study required changes to behaviour and systems, including the “surgical time-out” (STO), otherwise known as a briefing. The STO is used for operative staff to introduce one another, and to discuss and confirm the name of the patient, the procedure and site of the procedure, and any anticipated critical events. This is one of the key points at which the checklist also becomes a communication tool. The benefits of properly-conducted STOs are numerous. A recent study showed that they reduced communication failures by two-thirds, reduced non-routine events by one-quarter, discovered potential surgical safety hazards, lowered staff perception of risk, and increased team collaboration.[6] Further, a “powerful link” between routinely undertaking STOs and safety culture has been found.[7]

Checklists are relatively cheap, easy and low-tech tools for managing complexity, in a world of increasing complexity. They help organize information to remind practitioners about basic steps for specific procedures, while the practitioners focus on the technical knowledge and expertise needed to complete the actual procedure. When embraced by practitioners, checklists make a meaningful contribution to a culture of patient safety and quality improvement.

Next: The Limitations of Checklists


[1] George, Fred. “Checklists and Callouts: Keep It Simple, Avoid Distraction, Prevent Ineptitude,” Aviation Week Network (April 30, 2015) accessed online at online at

[2] Degani, Asif and Earl L. Weiner, “Cockpit Checklists: Concepts, Design and Use,” Human Factors 35(2) (1993): 28-43.

[3] “Human Factors” is the field of study dedicated to examining the interface between humans and technologies, tools, environments and systems.

[4] Gawande, Atul, “The checklist,” New Yorker (December 10 2007) accessed online at

[5] Gawande, Atul, The Checklist Manifesto: How to Get Things Right (New York: Metropolitan Books, Henry Holt and Company, 2009).

[6] Civil, Ian and Carl Shuker, “Briefings and debriefings in one surgeon’s practice,” ANZ Journal of Surgery (April 21, 2015) accessed online at at

[7] Allard J, et al., “Pre-surgery briefings and safety climate in the operating theatre,” BMJ Qual Saf 20(8) (2011): 711–7.