Usability

Jamie Z 2025-04-22

Usability Principles

Useability is a user-centric set of principles that aim to improve the user experience by making computers easier to use.

Accessibility

Accessibility is the ability of a product to be used by many different people, even people with disabilities.

The practice of making sites accessible also benefits other groups such as those using mobile devices, or those with slow network connections.

Accessibility has four different components:

Perceivable - Information and user interface components must be presented to users in ways they can perceive. This means that users must be able to perceive the information being presented (it can’t be invisible to all of their senses) - it must be visual, audible in our context as no haptic feedback or taste or texture
Operable - User interface components and navigation must be operable. This means that users must be able to operate the interface (the interface cannot require interaction that a user cannot perform)
Understandable - Information and the operation of user interface must be understandable. This means that users must be able to understand the information as well as the operation of the user interface (the content or operation cannot be beyond their understanding)
Robust - Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies. This means that users must be able to access the content as technologies advance (as technologies and user agents evolve, the content should remain accessible)

Utility

Utility is concerned with the ability of the system to provide all the functionality that users need.

It is a measure of how much satisfaction or happiness that a person gains from a particular application. Users are often willing to cope with some difficulty of use in a system that provides critically needed functionality.

Essentially, utility is a measure of how useful a digital solution is to the user.

There are two ideas that need to be considered when determining the utility of a system:

• How high is the ease of use (EOU) of the solution?

• What degree of usefulness does the solution provide? What can it do for the user?

Effectiveness

Effectiveness is concerned with the ability of users to use the system to do the work they need to do, includes reliability.

If a system is reliable it is constant and dependable or consistent and repeatable. When you evaluate effectiveness you are looking for things that work or do not work as expected.

Safety

Safety considers the questions:

How many errors do users make?
How severe are these errors?
How easily can the user recover from the errors?
Safety is a little considered usability goal. Safety is protecting the users from dangerous errors, for example losing all the user’s data or protecting the user’s confidential information.

Examples of designing safely could include:

Not putting the delete button next to the save button. Providing users various ways to recover from errors, both by reverting to a priority state or progressing the system to the correct state. For example in a word processor, the writer can use control-z to correct, back button, or retype to correct mistake
Making sure that input text field are wide enough to hold all the required data.

Learnability

Learnability includes how quickly and easily users can learn to: Find information Complete tasks Navigate the digital solution.

Qlearn shows you your upcoming assessments, and you can see all your lessons in each subject
The user interface is simple and easy to learn because each button is large and labeled
The user interface has colour contrast and large fonts, so it is accessible for users who have bad eyesight
The system is reliable and never changes depending on the subject. The submit button always works, and so do the download links.
An example of design safety is the ability to re-submit your assignment in case you submit the wrong file