According to data published by researchers at the Harvard T.H. Chan School of Public Health, more than 234 million major surgical procedures are conducted around the world every year. While most of these surgeries are successful, millions of patients die needlessly due to hospital-acquired infections, surgeon error, and other complications that are easily preventable.

Troubled by the scale of the injuries and death suffered by surgical patients, researchers at the World Health Organization (WHO) developed a pioneering technique that could potentially save countless millions of lives. The WHO's solution wasn't a bold innovation in operating-room technology, a radical new surgical technique, or an experimental wonder drug.

It was a simple checklist.

Developed by renowned author and surgeon Atul Gawande, the checklist takes mere minutes to complete and provides physicians with guidance at three crucial stages of surgical procedures: before the patient undergoes anesthesia, before the first incision is made, and before the patient is transferred from the operating room to a recovery ward. Gawande's checklist has already shown incredible potential and will not only save millions of lives but also potentially billions of dollars.

A checklist is much more than a simple organizational tool—it's a way to manage complexity on behalf of our users. They offer a visual representation of a user's place in the broader journey, help reinforce a sense of accomplishment, and help people identify urgent priorities.

Why are checklists so effective? Because of how our minds work.

Understanding—and Applying—the Psychology of Checklists to UX

As UX practitioners, it's our job to help users accomplish their goals. But users often fail to do so when using our products. Why? Sometimes it's our fault: Maybe our UX writing isn't as clear as we think it is, or we unintentionally hide crucial navigational elements behind confusing design decisions.

But what about when we're sure that it isn't our fault?

The Principle of Least Effort in UX

According to a landmark paper published by philosophers Samuel Gorovitz and Alasdair MacIntyre in the 1970s, there are two main reasons people fail: ignorance and ineptitude. We fail because we either don't have enough information to complete a task successfully—ignorance; or we lack the skill or ability required to complete the task itself—ineptitude.

The real question is why people still fail when they have both the information necessary to complete a task and the skill or aptitude to do so.

The answer lies in what Nobel Prize–winning psychologist Daniel Kahneman describes as the two modes of thinking that we rely upon in everyday life:

  • Mode 1: The first mode of thinking lets us function with minimal cognitive effort. Similar to “muscle memory,” this mode governs the things we do almost automatically every day with little or no thought. These actions feel natural and intuitive, and this mode of thinking is incredibly fast.
  • Mode 2: The second mode of thinking tackles major decisions and complex problem-solving tasks. Unlike the first mode, this way of thinking is slow and deliberate and takes considerable cognitive effort.

When we think about how we make decisions throughout our day, it's hardly surprising that most people prefer to rely on the first mode of thinking; it's faster and easier and takes a lot less effort.

This is why your users love checklists. They allow the user to rely on that quick, intuitive, easier mode of thinking while helping them accomplish their goals.

Virtually everyone has used a checklist at one point or another, whether it's to go shopping for groceries or plan for a vacation. This familiarity is an invaluable asset to us as UX practitioners. Users know what checklists are, what they're for, and how they work. Not only that, but they understand checklists in that first mode of thinking—quickly, intuitively, and easily. Incorporating a checklist into our products means that almost no cognitive effort has to be expended by the user to understand what to do and what's expected of them.

Another advantage of checklists is that they're concise by nature; they present the user with the minimum amount of information needed to get the job done. This in turn eliminates decision fatigue—another important psychological win for our users. Checklists also help users take actions quickly with minimal effort that support their decision-making process, which is a fundamental part of onboarding UX.

Online payments-processing service PayPal leverages checklists to great effect as part of its onboarding UX for new business-account holders.  

Recognizing that opening a business account may be intimidating for new users, PayPal has smartly incorporated the checklist above into its onboarding UX flow to provide users with a visual representation of the entire sign-up process. This tells the user right away that there are only five steps, which significantly reduces the perceived effort involved in creating a new account. It also leverages both check marks and color to reinforce the familiarity of the checklist itself, further reinforcing how many steps the user has left to complete. Finally, the copy on this page is simple and concise, and logical icons frame each step within the context of the next, which significantly reduces ambiguity.

The inclusion of this checklist takes the pressure off the user to identify, find, and recall crucial information during the sign-up process and assumes this burden itself. This helps new users rely on their fast, intuitive mode of thinking instead of asking them to expend significant cognitive effort.

The Power of 'Cognitive Closure' in UX

If you've ever felt regretful or guilty about failing to complete a task, you're at least somewhat familiar with a psychological phenomenon known as the Zeigarnik effect. Named after the Lithuanian psychologist who first discovered and documented it, the Zeigarnik effect refers to the fact that people can often remember incomplete tasks much more effectively than completed tasks purely because they have not yet finished what they set out to do.

Zeigarnik also found that people are much more likely to be motivated to complete tasks left unfinished. However, the Zeigarnik effect often coincides with another psychological phenomenon known as the goal-gradient effect. Popularized in the 1930s by American psychologist Clark Hull, the goal-gradient effect describes situations in which people's motivation to complete a task is significantly higher the closer the task is to completion. This is why so many fundraisers tend to accelerate the closer they get to their fundraising goals—everybody wants to see the project cross the finish line.

This is another reason why checklists can be so powerful in UX: They offer our users a clear visual representation of how far along they are in an ongoing process—and how close the users are to the satisfaction of completing it.

Project management app Monday leverages both the Zeigarnik and goal-gradient effects masterfully in its profile-completion checklist, as you can see above. This element of Monday's onboarding UX is crucial; the more complete a user's profile is, the more value that user is likely to get from the product. That in turn boosts retention. This particular checklist also makes excellent use of both color and a highly familiar check-marks and a progress-indicator bar to reiterate to the user where they are in the process, what tasks they've completed thus far, and how many additional steps they have left to complete.

The Psychology of Small Wins and Big Rewards

Not so long ago, talk of neurotransmitters and dopamine—the chemical in our brains that makes us feel good when we do something rewarding—was largely confined to conversations between physicians or to the pages of medical journals. Today, however, many people are aware of dopamine and the crucial role it plays in governing behavior, particularly within the context of technology and consumer products.

When we complete a task or achieve success, dopamine is released into our bloodstream. Along with endorphins, oxytocin, and serotonin, the release of dopamine makes us feel good, helps us concentrate, and makes us want to continue doing the activity or task that has made us feel good in the first place. Put another way, dopamine is the magic ingredient in fantastic user experiences.

But if a task proves too difficult or frustrating, the exact opposite happens: We become irritable, find it much harder to concentrate, and are much less likely to attempt the task again.

As UX practitioners, it's our job to design and craft user experiences that help our users achieve those incredibly satisfying and rewarding winning streaks. When we design experiences that empower users to win frequently, their sense of productivity and achievement is much stronger—as is the subsequent dopamine hit. Frequent wins also help our users maintain their concentration, which in turn helps them feel like the time and effort they invest in our products is well spent.

When it comes to helping users get on that crucial winning streak, there are few tools in our UX toolbox as effective as the humble checklist. That's because checklists break complex tasks into manageable actions that are much less intimidating than the sum of those actions. By reducing the time, effort, and energy required to complete a task, checklists give our users those frequent, periodic dopamine hits they need to feel engaged, motivated, and satisfied.

One of the best examples of this principle in action is online technology-training site Treehouse.  

Treehouse understands how daunting learning to program can be. Due to the inherent complexity of the topics Treehouse teaches, such as object-oriented programming and server-side web development, the path to even a basic understanding of these topics can seem overwhelming.

That's what makes Treehouse's progression pathways so clever. By breaking up a complex and potentially intimidating goal—learning the Ruby on Rails development framework, for example—into short, manageable subtasks, Treehouse users can achieve a satisfying winning streak, see where they are in the course's broader syllabus, and see how far they've come. This reinforces that vital sense of winning and satisfaction that can help students maintain their motivation over time and master even the most complex topics.

Helping Users Win? Check

The real beauty of checklists is their simplicity, elegance, and practicality.

Checklists help us protect surgical patients, learn new languages, improve our productivity, and so much more. We use them at home, at the office, at the grocery store—everywhere.

Checklists are a fundamental part of good UX, and hopefully it's easier to see why. During your next UX project, resist the temptation to try to reinvent the wheel for its own sake, and instead consider using one of the most reliable, effective, and powerful tools at your disposal. Your users will thank you for it—and they'll feel great doing it.