Heuristic Evaluation

Number of Evaluators

The heuristic evaluation can be done by only one evaluator, or more evaluators independently. Single evaluators will tend to miss a lot of problems, and it is a good practice to use between 4 - 8 evaluators at a time. At the end of the process, they can compare their findings and will have much better results.

Heuristic Principles

Each team can build its list of heuristic principles, but by far the most used and known list of heuristic principles in the UX design world is Jakob Nielsen's 10 Usability Heuristics. Let's find out what are those.

1. Visibility of system status

A system should always keep users informed about what is going on, through feedback in real-time. By knowing what the current status is, a user can change it and have a better understanding of what you need to do to reach your goal. For instance, when you make a payment online, you need to know that payment was approved and everything went well, without having to go to the bank.

2. Match between system and the real world

People find comfort in familiarity, this is the reason why this principle is so important in Jakob Nielsen's view. If people don't understand the terms used in a system, they will feel unsure and feel forced to go elsewhere to find explanations and complete their goals. The system should always speak the users' language, and use concepts familiar to the user.

3. User control and freedom

The users should always be given the ability to control and have the freedom to undo, and redo their performed intentional & unintentional actions. Make sure your design allows users to learn by exploring, poking around, trying things out. This means consequences of errors need to be less severe.

Example: Dialog, operations should have a Cancel option.

4. Consistency and standards

Users should not have to wonder whether different words, situations, or actions mean the same thing across an interface/system. You need to make sure the same words mean the same thing and launch the same action in your interface. Also, your design needs to have external consistency too. People come to your UI with existing expectations for how things should work and where they should be placed.

5. Error prevention

Prevent unconscious errors by either eliminating error-prone conditions or present users with a confirmation option before they commit to the action.

6. Recognition rather than recall

Users should not have to remember what certain things do from one place to another, this is why you should minimize the user's memory load. Make objects, actions, and options visible. People have limited short-term memories, designs that promote recognition reduce the amount of cognitive effort required from users.

7. Flexibility and efficiency of use

Designers often focus only on first-time users, but once a system is used again and again, users need ways to speed up their process. A system should cater to both new users and expert users by including accelerators, meaning having multiple ways and methods for accomplishing certain routine tasks quickly and easily.

8. Aesthetic and minimalist design

Remove unnecessary elements from the interface and focus on the essentials. Create less noise and distractions in your design, and let users have a smoother experience and faster way to accomplish their goals.

9. Help users recognize, diagnose, and recover from errors

The simple 3 steps to respect this principle are the following:

• inform users when an error has occurred

• tell users exactly what the problem is, using plain language (no codes)

• offer a way/solution to fix the error

10. Help and documentation

Things like onboarding pages, tooltips, walkthroughs, videos, chatbots, comprehensive FAQs, are great ways to provide help and documentation.

Exercise: Heuristic Evaluation

Let's do a quick heuristic evaluation of a flight booking website that will help us understand better what we've learnt above. I have chosen a flight booking website, because these type of services are often times really confusing and tend to have lots of problems.

Let's book a flight using www.cheapflights.com. When I am choosing the dates for my trip, the days boxes change colors and gives me good "Visibility of System status", helping me have a better understanding of time period between flights.

Once I clicked "Find a deal", nothing happened. I had to look around and see what is happening. After a while I thought to check the boxes from the right window, and select "compare selected". This is not a very big issue, but it doesn't do a good job at "Consistency and standards", I expected the system to work differently than it did.

After I clicked "Compare Selected" button, the website does a good job at "Error prevention" with the "please don't refresh" caption, and offers great "Visibility of System status" with the loading bar.

I ended up on https://www.edreams.net website. So I'm no longer on cheapflights.com. The website provides good "Help and documentation", letting me know right away about a piece of information that is very important for me, the free re-booking and trip cancellation insurance options.

Moving forward to selecting my flights. I find an almost perfect "Help users recognize, diagnose, and recover from errors" heuristic. The website lets me know there's an error, and where the error is. It could be more exact, for example : "Please choose a time for your return trip", and highlight the last 2 rows that I just didn't see the first time.

Going forward, while I was filling in my details, this message appears out of nowhere. I did not know I had to hurry, that there is a clock ticking somewhere, no documentation, nothing. This checks multiple errors for the following things: Visibility of system status, Consistency and standards, Error prevention, Help users recognize, diagnose, and recover from errors, Help and documentation.

Another problem I found was a combination "of Aesthetic and minimalist design", "Consistency and standards" and "Visibility of system status". After I choose the "Basic" plan, I kept clicking "Basic", even after the button changed to "Added". Because I mistook the green rectangle over the "Standard" plan as a selected box, and didn't know how to select something else.

Conclusion

To gain more experience with Jakob Nielsen's 10 Usability Heuristics, start checking lots of websites and apps online; study and note down everything you find, the good and the bad. This is a great exercise that will help you grow your UX design skills.