The Checklist Manifesto

by Atul Gawande

  With the checklist in place, the team had its first success--the rescue of the three-year-old girl. Not long afterward, Thalmann left to take a job at a hospital in Vienna. The team, however, has since had at least two other such rescues, he said. In one case, a man had been found frozen and pulseless after a suicide attempt. In another, a mother and her sixteen-year-old daughter were in an accident that sent them and their car through a guardrail, over a cliff, and into a mountain river. The mother died on impact; the daughter was trapped as the car rapidly filled with icy water. She had been in cardiac and respiratory arrest for a prolonged period of time when the rescue team arrived.

  From that point onward, though, everything moved like clockwork. By the time the rescue team got to her and began CPR, the hospital had been notified. The transport team delivered her in minutes. The surgical team took her straight to the operating room and crashed her onto heart-lung bypass. One step followed right after another. And, because of the speed with which they did, she had a chance.

  As the girl's body slowly rewarmed, her heart came back. In the ICU, a mechanical ventilator, fluids, and intravenous drugs kept her going while the rest of her body recovered. The next day, the doctors were able to remove her lines and tubes. The day after that, she was sitting up in bed, ready to go home.

  3. THE END OF THE MASTER BUILDER

  Four generations after the first aviation checklists went into use, a lesson is emerging: checklists seem able to defend anyone, even the experienced, against failure in many more tasks than we realized. They provide a kind of cognitive net. They catch mental flaws inherent in all of us--flaws of memory and attention and thoroughness. And because they do, they raise wide, unexpected possibilities.

  But they presumably have limits, as well. So a key step is to identify which kinds of situations checklists can help with and which ones they can't.

  Two professors who study the science of complexity--Brenda Zimmerman of York University and Sholom Glouberman of the University of Toronto--have proposed a distinction among three different kinds of problems in the world: the simple, the complicated, and the complex. Simple problems, they note, are ones like baking a cake from a mix. There is a recipe. Sometimes there are a few basic techniques to learn. But once these are mastered, following the recipe brings a high likelihood of success.

  Complicated problems are ones like sending a rocket to the moon. They can sometimes be broken down into a series of simple problems. But there is no straightforward recipe. Success frequently requires multiple people, often multiple teams, and specialized expertise. Unanticipated difficulties are frequent. Timing and coordination become serious concerns.

  Complex problems are ones like raising a child. Once you learn how to send a rocket to the moon, you can repeat the process with other rockets and perfect it. One rocket is like another rocket. But not so with raising a child, the professors point out. Every child is unique. Although raising one child may provide experience, it does not guarantee success with the next child. Expertise is valuable but most certainly not sufficient. Indeed, the next child may require an entirely different approach from the previous one. And this brings up another feature of complex problems: their outcomes remain highly uncertain. Yet we all know that it is possible to raise a child well. It's complex, that's all.

  Thinking about averting plane crashes in 1935, or stopping infections of central lines in 2003, or rescuing drowning victims today, I realized that the key problem in each instance was essentially a simple one, despite the number of contributing factors. One needed only to focus attention on the rudder and elevator controls in the first case, to maintain sterility in the second, and to be prepared for cardiac bypass in the third. All were amenable, as a result, to what engineers call "forcing functions": relatively straightforward solutions that force the necessary behavior--solutions like checklists.

  We are besieged by simple problems. In medicine, these are the failures to don a mask when putting in a central line or to recall that one of the ten causes of a flat-line cardiac arrest is a potassium overdose. In legal practice, these are the failures to remember all the critical avenues of defense in a tax fraud case or simply the various court deadlines. In police work, these are the failures to conduct an eyewitness lineup properly, forgetting to tell the witness that the perpetrator of the crime may not be in the lineup, for instance, or having someone present who knows which one the suspect is. Checklists can provide protection against such elementary errors.

  Much of the most critical work people do, however, is not so simple. Putting in a central line is just one of the 178 tasks an ICU team must coordinate and execute in a day--ICU work is complicated--and are we really going to be able to create and follow checklists for every possible one of them? Is this even remotely practical? There is no straightforward recipe for the care of ICU patients. It requires multiple practitioners orchestrating different combinations of tasks for different conditions--matters that cannot be controlled by simple forcing functions.

  Plus, people are individual in ways that rockets are not--they are complex. No two pneumonia patients are identical. Even with the same bacteria, the same cough and shortness of breath, the same low oxygen levels, the same antibiotic, one patient might get better and the other might not. A doctor must be prepared for unpredictable turns that checklists seem completely unsuited to address. Medicine contains the entire range of problems--the simple, the complicated, and the complex--and there are often times when a clinician has to just do what needs to be done. Forget the paperwork. Take care of the patient.

  I have been thinking about these matters for a long time now. I want to be a good doctor for my patients. And the question of when to follow one's judgment and when to follow protocol is central to doing the job well--or to doing anything else that is hard. You want people to make sure to get the stupid stuff right. Yet you also want to leave room for craft and judgment and the ability to respond to unexpected difficulties that arise along the way. The value of checklists for simple problems seems self-evident. But can they help avert failure when the problems combine everything from the simple to the complex?

  I happened across an answer in an unlikely place. I found it as I was just strolling down the street one day.

  It was a bright January morning in 2007. I was on my way to work, walking along the sidewalk from the parking lot to the main entrance of my hospital, when I came upon a new building under construction for our medical center. It was only a skeleton of steel beams at that point, but it stretched eleven stories high, occupied a full city block, and seemed to have arisen almost overnight from the empty lot that had been there. I stood at one corner watching a construction worker welding a joint as he balanced on a girder four stories above me. And I wondered: How did he and all his co-workers know that they were building this thing right? How could they be sure that it wouldn't fall down?

  The building was not unusually large. It would provide 150 private hospital beds (so we could turn our main tower's old, mostly shared rooms into private beds as well) and sixteen fancy new operating rooms (which I was especially looking forward to)--nothing out of the ordinary. I would bet that in the previous year dozens of bigger buildings had been constructed around the country.

  Still, this one was no small undertaking, as the hospital's real estate manager later told me. The building, he said, would be 350,000 square feet in size, with three stories underground in addition to the eleven stories above. It would cost $360 million, fully delivered, and require 3,885 tons of steel, thirteen thousand yards of concrete, nineteen air handling units, sixteen elevators, one cooling tower, and one backup emergency generator. The construction workers would have to dig out 100,000 cubic yards of dirt and install 64,000 feet of copper piping, forty-seven miles of conduit, and ninety-five miles of electrical wire--enough to reach Maine.

  And, oh yeah, I thought to myself, this thing couldn't fall down.

  When I was eleven years old, growing up in Athens, Ohio, I decided I was going
to build myself a bookcase. My mother gave me ten dollars, and I biked down to the C&E Hardware store on Richland Avenue. With the help of the nice man with hairy ears behind the counter, I bought four pine planks, each eight inches wide and three-quarters of an inch thick and cut to four feet long. I also bought a tin of stain, a tin of varnish, some sandpaper, and a box of common nails. I lugged the stuff home to our garage. I carefully measured my dimensions. Then I nailed the two cross planks into the two side planks and stood my new bookcase up. It looked perfect. I sanded down the surfaces, applied the stain and soon the varnish. I took it to my bedroom and put a half dozen books on it. Then I watched the whole thing fall sideways like a drunk tipping over. The two middle boards began pulling out. So I hammered in a few more nails and stood the bookcase up again. It tipped over the other way. I banged in some more nails, this time coming in at an angle, thinking that would do the trick. It didn't. Finally, I just nailed the damn thing directly into the wall. And that was how I discovered the concept of bracing.

  So as I looked up at this whole building that had to stand up straight even in an earthquake, puzzling over how the workers could be sure they were constructing it properly, I realized the question had two components. First, how could they be sure that they had the right knowledge in hand? Second, how could they be sure that they were applying this knowledge correctly?

  Both aspects are tricky. In designing a building, experts must take into account a disconcertingly vast range of factors: the makeup of the local soil, the desired height of the individual structure, the strength of the materials available, and the geometry, to name just a few. Then, to turn the paper plans into reality, they presumably face equally byzantine difficulties making sure that all the different tradesmen and machinery do their job the right way, in the right sequence, while also maintaining the flexibility to adjust for unexpected difficulties and changes.

  Yet builders clearly succeed. They safely put up millions of buildings all over the globe. And they do so despite the fact that construction work has grown infinitely more complex over the decades. Moreover, they do it with a frontline workforce that regards each particular job--from pile-driving to wiring intensive care units--much the way doctors, teachers, and other professionals regard their jobs: as specialized domains in which others should not interfere.

  I paid a visit to Joe Salvia, the structural engineer for our new hospital wing. I told him I wanted to find out how work is done in his profession. It turned out I'd come to the right person. His firm, McNamara/Salvia, has provided the structural engineering for most of the major hospital buildings in Boston since the late 1960s, and for a considerable percentage of the hotels, office towers, and condominiums as well. It did the structural rebuilding of Fenway Park, the Boston Red Sox baseball team's thirty-six-thousand-seat stadium, including the Green Monster, its iconic thirty-seven-foot, home-run-stealing left field wall. And the firm's particular specialty has been designing and engineering large, complicated, often high-rise structures all over the country.

  Salvia's tallest skyscraper is an eighty-story tower going up in Miami. In Providence, Rhode Island, his firm built a shopping mall that required one of the largest steel mill orders placed on the East Coast (more than twenty-four thousand tons); it is also involved in perhaps the biggest commercial project in the world--the Meadowlands Xanadu entertainment and sports complex in East Rutherford, New Jersey, which will house a stadium for the New York Giants and New York Jets football teams, a three-thousand-seat music theater, the country's largest movie multiplex, and the SnowPark, the nation's first indoor ski resort. For most of the past several years, McNamara/Salvia's engineers have worked on fifty to sixty projects annually, an average of one new building a week. And they have never had a building come even close to collapsing.

  So I asked Salvia at his office in downtown Boston how he has ensured that the buildings he works on are designed and constructed right. Joe Salvia is sixty-one, with almost no hair, a strong Boston accent, and a cheery, take-your-time, how-about-some-coffee manner that I didn't expect from an engineer. He told me about the first project he ever designed--a roof for a small shopping plaza.

  He was just out of college, a twenty-three-year-old kid from East Cambridge, which is not exactly where the Harvard professors live. His father was a maintenance man and his mother worked in a meat processing plant, but he was good in school and became the first member of his family to go to college. He went to Tufts University planning to become a doctor. Then he hit organic chemistry class.

  "They said, 'Here, we want you to memorize these formulas,' " he explained. "I said, 'Why do I have to memorize them if I know where the book is?' They said, 'You want to be a doctor? That's what you have to do in medicine--you have to memorize everything.' That seemed ridiculous to me. Plus I wasn't good at memorizing. So I quit."

  But Salvia was good at solving complex problems--he tried to explain how he solves quadratic equations in his head, though all I managed to pick up was that I'd never before heard someone say "quadratic equation" in a Boston accent. "I also liked the concept of creating," he said. As a result, he switched to engineering, a scientific but practical field, and he loved it. He learned, as he put it, "basic statics and dynamics--you know, F equals ma," and he learned about the chemistry and physics of steel, concretes, and soil.

  But he'd built nothing when he graduated with his bachelor's degree and joined Sumner Shane, an architectural engineering firm that specialized in structural engineering for shopping centers. One of its projects was a new shopping mall in Texas, and Salvia was assigned the roof system. He found he actually understood a lot about how to build a solid roof from his textbooks and from the requirements detailed in building codes.

  "I knew from college how to design with structural steel--how to use beams and columns," he said. And the local building codes spelled out what was required for steel strength, soil composition, snow-bearing capacity, wind-pressure resistance, and earthquake tolerance. All he had to do was factor these elements into the business deal, which specified the size of the building, the number of floors, the store locations, the loading docks. As we talked he was already drawing the contours for me on a piece of paper. It started out as a simple rectangle. Then he sketched in the store walls, doorways, walking space. The design began taking form.

  "You draw a grid of likely locations to carry the roof weight," he said, and he put in little crosses where columns could be placed. "The rest is algebra," he said. "You solve for X." You calculate the weight of the roof from its size and thickness, and then, given columns placed every thirty feet, say, you calculate the diameter and strength of the column required. You check your math to make sure you've met all the requirements.

  All this he had learned in college. But, he discovered, there was more--much more--that they hadn't taught him in school.

  "You know the geometric theory of what is best, but not the practical theory of what can be done," he said. There was the matter of cost, for example, about which he had not a clue. The size and type of materials he put in changed the cost of the project, it turned out. There was also the matter of aesthetics, the desires of a client who didn't want a column standing in the middle of a floor, for instance, or blocking a particular sightline.

  "If engineers were in charge, every building would be a rectangular box," Salvia said. Instead, every building is new and individual in ways both small and large--they are complex--and as a result there is often no textbook formula for the problems that come up. Later, for example, when he established his own firm, he and his team did the structural engineering for Boston's International Place, a landmark forty-six-story steel and glass tower designed by the architect Philip Johnson. The building was unusual, a cylinder smashed against a rectangle, a form that hadn't been tried in a skyscraper before. From a structural engineering point of view, Salvia explained, cylinders are problematic. A square provides 60 percent more stiffness than a circle, and in wind or an earthquake a building needs to be
able to resist the tendency to twist or bend. But a distorted cylinder it was, and he and his team had to invent the engineering to realize Johnson's aesthetic vision.

  Salvia's first mall roof may have been a simpler proposition, but it seemed to him at the time to have no end of difficulties. Besides the concerns of costs and aesthetics, he also needed to deal with the requirements of all the other professionals involved. There were the plumbing engineers, the electrical engineers, the mechanical engineers--every one of them wanting to put pipes, wiring, HVAC units just where his support columns were supposed to go.

  "A building is like a body," he said. It has a skin. It has a skeleton. It has a vascular system--the plumbing. It has a breathing system--the ventilation. It has a nervous system--the wiring. All together, he explained, projects today involve some sixteen different trades. He pulled out the construction plans for a four-hundred-foot-tall skyscraper he was currently building and flipped to the table of contents to show me. Each trade had contributed its own separate section. There were sections for conveying systems (elevators and escalators), mechanical systems (heating, ventilation, plumbing, air conditioning, fire protection), masonry, concrete structures, metal structures, electrical systems, doors and windows, thermal and moisture systems (including waterproofing and insulation), rough and finish carpentry, site work (including excavation, waste and storm water collection, and walkways)--everything right down to the carpeting, painting, landscaping, and rodent control.

  All the separate contributions had to be included. Yet they also had to fit together somehow so as to make sense as a whole. And then they had to be executed precisely and in coordination. On the face of it, the complexities seemed overwhelming. To manage them, Salvia said, the entire industry was forced to evolve.