Nielsen's Heuristics

Think back to the last time you tried to assemble a piece of furniture with a poorly-written instruction manual—we’ve all been there. Manuals are notoriously filled with technical jargon, complicated images, and steps that test the limits of our short-term memory. They’re often riddled with inconsistent styling and icons that seem to mean different things from page to page. Perhaps we can find our way with the help of troubleshooting tips, or at least a number to call for support, but what if this information is lacking as well? A bad website is a lot like a confusing manual—both can leave users feeling frustrated and lost.

How do the best designers ensure their websites are effortlessly usable? They refer to design principles, called usability heuristics, that outline tried and tested practices for user-friendly design.

Jakob Nielsen, a prominent web usability expert, is responsible for establishing the most popular and frequently used set of usability heuristics that exist today. Nielsen’s heuristics are 10 general principles of digital interface design based on the problems real users face when using digital systems.

Importantly, Nielsen’s heuristics are not hard and fast guidelines, but general rules of thumb.¹ The term “heuristics” is used to describe the nature of these principles as design shortcuts. They are meant to be broad enough to adapt to varying situations based on how users typically think and behave. 

Here’s a brief rundown of Nielsen’s 10 usability heuristics:²

1. Visibility of System Status: Users should always know what’s going on with a website or program through consistent and timely feedback. For example, interfaces should make it obvious when a button is clicked, an item is added to a shopping cart, or a page is actively loading. This gives users confidence that they have control over the system and helps them plan their next steps.
2. Match Between the System and the Real World: Interfaces should communicate with users through concepts and phrases that are familiar to them. As such, designs should align with the users’ everyday language and experiences, avoiding internal jargon and unfamiliar terminology. For example, navigation menus should use labels like “About Us” and “Blog” that people already know and understand.
3. User Control and Freedom: Designs should have a clearly marked “emergency exit” that allows users to undo accidental actions or leave a digital process. Undo, redo, exit, and cancel buttons are excellent examples here. These features give users the freedom to use an interface without getting stuck.
4. Consistency and Standards: Designs should align with user expectations by following established conventions commonly found in other digital designs. Internally, designs should use consistent terminology and elements across all pages. This prevents users from having to learn something new to use the design, reducing their cognitive load and improving usability.
5. Error Prevention: Errors and mistakes should be avoided with safeguards built into the design. For example, this might mean asking users for confirmation before executing an irreversible action, such as deleting an account or completing a purchase.
6. Recognition Rather than Recall: The system should reduce the amount of information users have to remember by making cues (options, actions, and elements) visible. It’s easier for people to recognize information than remember it, so this heuristic reduces the cognitive effort required to use a design.
7. Flexibility and Efficiency of Use: Designs should cater to both novice and expert users. Ideally, experienced users should be able to leverage shortcuts and customize the interface to make repetitive processes more efficient. This is a common design feature in photo editing software, word processing tools, and project management platforms.
8. Aesthetic and Minimalist Design: Eliminate unnecessary information that can distract users from the information they need. Designers can do this by adopting a minimal approach to design and establishing a clear hierarchy of information on the page, which keeps users focused on essential elements that are key to usability, like buttons and links.
9. Help Users Recognize, Diagnose, and Recover from Errors: Interfaces should communicate problems clearly and display error messages in plain language that users would understand. If possible, offer users a solution to the error, such as a shortcut to a customer support page. 
10. Help and Documentation: Ideally, systems should be designed to be as self-explanatory as possible. However, it’s often necessary to provide additional documentation to help users who require guidance or run into problems, especially with more complex software programs.

Although many of these heuristics sound fairly obvious, it’s easy to lose sight of the users’ needs when you’re focused on the technical aspects or aesthetics of a design. Stepping back and looking at a design from the perspective of the user allows usability problems to reveal themselves. Nielsen’s heuristics act as a cheat sheet or checklist, telling designers what issues to look for.

Heuristic Evaluation: A method for evaluating an interface to identify usability problems, typically done before testing on users. Heuristic evaluations are performed by a handful of specialists or evaluators with a thorough understanding of usability. Their goal is to evaluate how well a design complies with established usability principles, such as Nielsen’s heuristics, by looking for design problems that violate each heuristic.

User Interface (UI): The visible design of a website or application that allows for user interaction. The UI includes elements like buttons, images, text, and form fields that allow users to input information and view information output by the system. Most of Nielsen’s heuristics apply to the design of the UI (rather than the backend of the system that handles computing).

User Testing: A qualitative research method that involves testing a design with real users to discover pain points or opportunities to improve the user experience (UX). In a user test, users are observed as they interact with a system and attempt to complete certain tasks, like purchasing a product on an e-commerce website or downloading a file from a web application. 

Usability: How easy a UI is to use. More specifically, usability is a measure of how effectively and efficiently target users can use a system to achieve desired goals or complete tasks.

Mental Model: An internal representation of what users already believe about a system based on their past experiences. Mental models help users know what to expect so they can predict how a system will behave. Many of Nielsen’s heuristics help designers create systems that align with users’ mental models.

Nielsen published his 10 usability heuristics 30 years ago in 1994. Over the years, there has been a lot of speculation over how he developed these heuristics and whether they’re grounded in research or based purely on Nielsen’s subjective opinion. As you’ll soon see, the 10 heuristics do have a reliable scientific background.¹

The first set of Nielsen’s heuristics was developed in 1989. At the time, Nielsen was teaching a user interface course at the Technical University of Denmark with his colleague, Rolf Molich. The two professors needed a method for evaluating and grading their students’ UX exercises, and put their heads together to come up with a set of 10 usability heuristics. While these initial heuristics were not based on any kind of data, they laid the foundation for Nielsen’s later research.

In 1990, Nielsen moved to the U.S. to work at Bell Communications Research (also called Bellcore). Here, he researched usability testing methods, finding that Bellcore UX professionals relied on a combination of heuristic evaluation and user testing when designing products. He realized a need to refine his initial list of heuristics so they accurately reflected usability problems that occur in real-world systems.

Working at Bell presented a unique opportunity for Nielsen to identify and analyze a large number of usability problems facing UX projects. He identified 249 usability problems across 11 major Bellcore projects. At the same time, Nielsen created a list of 101 usability principles from existing UI research literature—which included his own 10 heuristics, of course.

Nielsen then combined his database of usability problems and usability principles in a matrix to evaluate how well each principle could explain each design problem.³ This matrix resulted in 25,149 data points. Next, he conducted a factor analysis—a statistical method used to condense and simplify a set of complex variables—to identify a few key correlations between usability problems and principles. The factor analysis revealed 10 factors that explained most of the 249 usability problems. Nielsen published his research along with his list of 10 heuristics in 1994, and the rest is history.

Jakob Nielsen: Danish web usability pioneer and expert in human-computer interaction. He has been crowned the “king of usability” and the “guru of web page usability” by various publications.⁴ Nielsen has written eight books, including the best-selling Designing Web Usability: The Practice of Simplicity and Usability Engineering. Nielsen co-founded the usability consulting company, Nielsen Norman Group (NN/g), in 1998 with Donald Norman, another notable usability expert.

Rolf Molich: Danish civil engineer and expert in human-machine interaction and user-friendly design.⁵ He co-invented the heuristic evaluation method with Nielsen when the two professors developed the initial set of 10 usability heuristics in 1989. Molich went on to found a usability consultancy, DialogDesign, in 1997 to help companies design usable IT systems.

Nielsen's heuristics likely played a role in the popularization of user-centered design through the 1990s and are still some of the most commonly used principles in UI design to this day. Thanks to heuristics, designers have a clear framework for designing digital products and evaluating their usability, ensuring designs work for users above all else.

This focus on user-friendly design has contributed to the development of intuitive products that everyone can understand and use—rather than products designed solely to be unique or “innovative.”

Essentially, Nielsen’s heuristics stress the importance of understanding behavioral science concepts when developing designs. As we touched on earlier, many heuristics explain how people form mental models of common design patterns and apply them to any new websites and programs they encounter.⁶ Jakob’s Law of the Internet User Experience sums this up nicely, stating that “users spend most of their time on other websites, so they expect your site to work like all the other sites they already know.” When designs go against these mental models, people run into usability issues. Nielsen’s heuristics provide a roadmap for ensuring websites align with user expectations.

Nielsen’s heuristics also have important commercial applications. By applying the heuristics to enterprise-level software, these tools become more efficient and user-friendly. This reduces the burden of training new users and improves software adoption by professionals. For example, one study used Nielsen's heuristics to evaluate the usability of commercial dental computer-based patient records (CPR).⁷ The researchers discovered significant usability problems in dental CPRs that could prevent professionals from using these systems effectively—and enjoying the patient care benefits that come with them.

Relying on Nielsen’s heuristics to make design decisions does have a few drawbacks. While the heuristics serve as excellent rules of thumb for general interface design, they are not specific enough to address targeted design challenges. How well would the heuristics work when evaluating a voice-controlled virtual assistant or a learning program designed for children? Fortunately, detailed usability guidelines exist for many of these specific scenarios. Nielsen’s heuristics are intended to be general, ensuring they are applicable across a wide range of design projects.

Some critics also question whether Nielsen’s heuristics are still useful for designing modern user interfaces.⁸ For example, the heuristics don’t address common issues with mobile app design, and several UX professionals have proposed new heuristics to evaluate mobile applications and identify related usability problems.⁹ This doesn’t mean Nielsen’s heuristics have become obsolete. The heuristics still effectively explain a range of usability problems, grounded in the real challenges people face when interacting with computers. After all, Nielsen’s heuristics have worked well for 30 years despite numerous changes in interface design trends.

Another issue with Nielsen’s heuristics is that they don’t necessarily reveal how users will react to designs. You can only gain these insights by testing designs on real users. It’s important to stress that heuristic evaluations are not meant to replace user testing. Nielsen himself is a strong proponent of user testing and acknowledges the value of extracting qualitative insights from research participants.¹

Heuristic evaluations are fantastic for identifying potential usability issues early in the design process before conducting user tests, which tend to be much more time-consuming and resource-heavy. The study on dental CPRs mentioned earlier actually compared heuristic evaluations against user testing and found that heuristic evaluations identified a significant number of the usability problems uncovered through subsequent usability testing.⁷ Notably, the researchers stated that Nielsen’s heuristics pointed out general usability problems that were later refined through user tests, displaying how well these two methods work together.

Many websites have been evaluated and improved using Nielsen’s heuristics. Let’s explore a case study of their use in identifying usability problems in a Learning Management System (LMS) for online undergraduate classes at Instituto Federal de Pernambuco (IFPE) in Brazil.¹⁰

Researchers sought to evaluate the usability of the LMS and identify opportunities to make the system more user-friendly. They performed heuristic evaluations using Nielsen’s heuristics and identified 54 usability problems. These are some of the most common issues identified and their associated heuristics:

• Poor consistency in the layout between pages (consistency and standards)
• Some buttons lacked labels or visual identifications of their functions (match between system and real world)
• The system lacked shortcuts for accessing certain features (flexibility and efficiency of use)
• Several times, it was not clear to the user whether or not their action was successful, like when logging in or updating their profile picture (visibility of system status)
• Many screens had excessive content that complicated the interface and pushed important information out of view (aesthetic and minimalist design)

The researchers confirmed that Nielsen’s heuristics were effective in highlighting several usability problems with the LMS. They also noted that they only needed four evaluators to uncover all these issues, pointing out the efficiency of this process. While observing real users as they navigated the LMS may have identified some additional issues, Nielsen’s heuristics allowed a small group of evaluators to identify several fundamental problems in a very short amount of time.

Usability Testing

Evaluating designs based on Nielsen’s heuristics is only half the battle. After identifying issues and implementing improvements, it’s important to test designs on real users through usability testing. This testing method involves observing how easily users can accomplish certain tasks and determining potential problems that are getting in their way.

UX Designer

UX designers are professionals with expertise in digital interface design. They’re responsible for ensuring interfaces are user-friendly and engaging by applying known design principles and conducting UX research to ensure systems align with the needs and behaviors of their target audience. UX designers are well-versed in Nielsen’s heuristics and often consider these design principles when making decisions.

1. Nielsen, J. (2024, February 15). How I Developed the 10 Usability Heuristics. UX Tigers. Retrieved March 27, 2024, from https://www.uxtigers.com/post/usability-heuristics-history
2. Nielsen, J. (1994, April 24). 10 Usability Heuristics for User Interface Design. Nielsen Norman Group. Retrieved March 27, 2024, from https://www.nngroup.com/articles/ten-usability-heuristics/
3. Nielsen, J. (1994): “Enhancing the explanatory power of usability heuristics,” in CHI '94: Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, 152-158. https://doi.org/10.1145/191666.191729
4. Nielsen, J. (n.d.). Dr. Jakob Nielsen biography | People. UX Tigers. Retrieved March 27, 2024, from https://www.uxtigers.com/about/people 
5. Molich, R. (n.d.). About Me – Rolf Molich. DialogDesign. Retrieved March 27, 2024, from https://www.dialogdesign.dk/about-rolf-molich/
6. Nielsen, J. (2023, September 8). Jakob's Law of the Internet User Experience. UX Tigers. Retrieved March 27, 2024, from https://www.uxtigers.com/post/jakobs-law
7. Thyvalikakath TP., Monaco V., Thambuganipalle H., & Schleyer T. (2009) Comparative study of heuristic evaluation and usability testing methods. Stud Health Technol Inform. 143. 322-327. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2736678/pdf/nihms138162.pdf
8. Gonzalez-Holland, E., Whitmer, D., Moralez, L., & Mouloua, M. (2017). Examination of the Use of Nielsen’s 10 Usability Heuristics & Outlooks for the Future. Proceedings of the Human Factors and Ergonomics Society Annual Meeting, 61(1), 1472-1475. https://doi.org/10.1177/1541931213601853 
9. Neto, O. & Pimentel, M. (2013). “Heuristics for the assessment of interfaces of mobile devices,” in WebMedia '13: Proceedings of the 19th Brazilian symposium on Multimedia and the web, 93-96. https://doi.org/10.1145/2526188.2526237
10. Penha, M. Correia, W., Campos, F., & Barros, M. (2014). Heuristic Evaluation of Usability - a Case study with the Learning Management Systems (LMS) of IFPE. International Journal of Humanities and Social Science. 4(6). 295-303. https://www.ijhssnet.com/journals/Vol_4_No_6_1_April_2014/32.pdf