Defining usability

Usability is a term we use regularly in design. We talk about the usability of an application or website, the functionality, and how we can best structure the interface so that it’s easy-to-use and intuitive. Since these terms are so widely used and thrown around, I thought it would be a good exercise to take a look at how some experts are defining usability and what we can learn from it. We can use these findings to continue to evolve our thinking on usability and design and become better designers. I also personally find it helpful to reflect on what we’ve done, what we’ve been doing, and how we can improve from time to time — hopefully this can be useful to you as well.

Steve Krug

I read a book by Steve Krug’s titled Don’t Make Me Think, Revisited: A Common Sense Approach to Web Usability a while ago and I remembered something that he said about usability. While I enjoyed his book, I really identified with this simplistic, yet powerful explanation of what usability is.

He defines usability like this,

A person of average (or even below average) ability and experience can figure out how to use the thing [i.e., it’s learnable] to accomplish something [effective] without it being more trouble than it’s worth [efficient].

Steve Krug

What I enjoy about this definition of usability is that he’s focusing on the average user. People are in a hurry and they don’t typically want to learn something new. So, if the average person can do what they need to do, and do it quickly — then you’ve done a good job.

Jacob Nielsen

Jacob Nielsen talks about usability quite a bit and I find his explanations quite good as well. Jakob Nielsen, the so-called “King of Usability” (crowned by Internet Magazine), writes the following in his article Usability 101: Introduction to Usability:

Usability is a quality attribute that assesses how easy user interfaces are to use. The word “usability” also refers to methods for improving ease-of-use during the design process.

Jacob Nielson

Furthermore, he goes on to explain that, “usability is defined by 5 quality components, which are,”

• Learnability: How easy is it for users to accomplish basic tasks the first time they encounter the design?
• Efficiency: Once users have learned the design, how quickly can they perform tasks?
• Memorability: When users return to the design after a period of not using it, how easily can they reestablish proficiency?
• Errors: How many errors do users make, how severe are these errors, and how easily can they recover from the errors?
• Satisfaction: How pleasant is it to use the design?

I think it’s important that Nielsen is discussing the quality of the design in regards to usability. In fact, the last bullet point about satisfaction directly relates to the quality of the overall design and how pleasing it is to work with. It’s also interesting that he specially calls out errors as being part of the components that make up usability. Evaluating the design on how many errors users encounter and how quickly they can recover is critical to the success of a website or app. This goes to show the importance of testing and refinements. Personally, I don’t think a design is ever really complete, it’s just completed for today. It’s something that should be continuously evolving.

Whitney Quesenbery

I’m a big fan of Whitney Quesenbery’s 5 Es of usability. They do a great job of explaining usability and providing a foundation to understanding well-structured websites and applications. Whitney writes, “The 5 Es of usability are (with goals attached),”

• Efficient — “The user will be able to successfully complete the registration in under 3 minutes”
• Effective — “Less than 5% of the registrations will have errors, omissions or inconsistencies requiring a follow-up contact by the staff.”
• Engaging — “At least 80% of employees will express comfort with using the online system rather than visiting the HR office.”
• Error Tolerant — “The system will validate all housing, meal and tutorial choices and allow the user to confirm pricing for these options before completing the registration.”
• Easy to Learn — “Users will be able to successfully complete a benefits calculation without needing any external instruction or help screens.”

You can read the full article on her website at wqusability.com. Her conclusion is this,

Usability and user-centered design are iterative. The work proceeds in a cycle of hypothesis and evaluation, with a picture of users and design solutions to meet their needs building in richness and completeness with each iteration. The five E’s (effective, efficient, engaging, error tolerant, easy to learn) provide the practitioner with a set of characteristics which can be used to organize and analyze information from users. They offer trace-ability from initial information-gathering through requirements setting and finally in evaluation. This might allow the understanding of the specific needs around each characteristic to grow, or be an opportunity to confirm whether the user requirements were chosen correctly in the early stages of the project. In either case, they let you go beyond “ease of use” in a practical way and help make it easier to make products more usable.

Whitney Quesenbery

User-Centered Design

Essentially, usability means user-centered design. It means really thinking about, studying, and evaluating how a user will interact and use your product, website, or application. User-centered design is about designing and optimizing for the user, not forcing them to change their behaviors or assumptions to learn and adapt to your product. It’s a really important philosophy in design and something that we at Rareview subscribe to heavily.

In user-centered design, it’s important to find the right balance between the following objectives:

Clarity

Clarity is essential. We define it as,

• Simplicity: Is your website simple? Is is easy to figure out and use, or is it overly complicated?
• Familiarity: Are users familiar with how to your your website? Are you designing the site in a logical, familiar way where the majority of people will immediately understand how to use it; or are you creating new terminology and processes that will be foreign to most users?
• Consistency: Are you being consistent throughout the full user experience? Are action buttons always placed in the same location with the same size and color as they are in other sections of your app? Are headings the same? Consistency means people have to think less.
• Feedback: This is an evolving process; are you considering, evaluating, and asking for user feedback? Are you using it to make your app better — more usable? Are you providing feedback to your users through the use of good, logical errors?

Intuitiveness

When we talk about a site being intuitive, we are also talking about familiarity (mentioned above in the Clarity section). Part of what makes a site intuitive is taking into account the notions and presumptions that already exist for the user about how to use a website. For example, the majority of users now know that the hamburger menu is used primarily in smaller displays to access the navigation. That functionality has become familiar (mostly second nature now) and therefore intuitive for users to automatically understand, without having to think about what that icon does. If we switch that with a new icon, say a sheet of paper that in our minds indicates “menu,” the user no longer subconsciously knows what that means and therefore what will happen if they click on that icon. We’ve therefore made the user have to stop and think, which means that it has become less intuitive.

Making your site intuitive is very important for increasing usability and decreasing frustration. Decreasing frustration is critical — how many times have you been on a site and you can’t find what you need, so you get frustrated, leave or fire off an email or chat because you need help? This is something we want to reduce as designers.

Credibility

For me, credibility not only takes into account the brand (Pepsi vs. Bill’s Online Diamond Shop), but also the design. You can easily spot a website or app that looks like it was done professionally. It has a great visual feel, it’s easy-to-use, it functions well, it has minimal errors — essentially, it’s been designed well and usability has been a key aspect during the design process. That establishes instant credibility. Compare that to a site that looks like it was created years ago, uses old technology, has blurry images, and the design is poor — and you’ll think twice about ordering or signing up on that site. This is web credibility.

Refinement

Design is an ever-evolving process. You design an interface, release it, and start getting immediate feedback from users. You need a long-term plan in place to handle changes and evolutions to the design, gathering user feedback and refining what isn’t working, and testing new ideas. A design is never complete. You should be testing, evaluating, and refining. Now…keep repeating this process.

In Summary

Usability is critical to good design. They go hand-in-hand. Design is not only about how something looks (form), but also about how it works (function). Thus, usability is essential to the design process.

At Rareview, we follow a design philosophy called User-Centered Design. If you’re interested in learning more about how we can help you construct, design, and build your website or application, please contact us.