What are the usability principles?
Usability is a quality of the user interface that refers to how easily and efficiently a user can perform a task on an interface. It's directly related to ease of use and ease of learning. In short, users should be able to easily accomplish their contextual goals using the interface without any need for extra knowledge or practice. Good interface designs tend to have a high level of usability.
Components
Usability comprises the following five components:
Learnability: It refers to how easily users can perform actions for the first time. Learnability principles are discussed in detail below.
Efficiency: Efficiency measures how quickly users can perform the tasks after they have learned the interface.
Memorability: It refers to how efficiently users can perform tasks on the interface when using it after some time.
Errors: This deals with errors' frequency, severity, and recoverability.
Satisfaction: Satisfaction concerns how enjoyable the interface experience was for users.
Principles
There are some principles that designers should incorporate into their design to maximize usability. These principles are divided into three broad categories:
Learnability
Flexibility
Robustness
Learnability principles
Learnability pertains to how easy it is for new users to perform initial interactions and continue with utmost performance. The following principles fall under the category of learnability principles.
Predictability: The principle of predictability states that the user should be able to predict the future interaction based on their previous history with the interface.
Synthesizability: Synthesizability refers to the interface allowing users to assess the effect of their actions on the system state.
Familiarity: The familiarity principle allows users to utilize prior knowledge to understand the interface's features.
Generalizability: Generalizability means that users can apply their experience of specific interfaces to new, similar ones.
Consistency: Consistency means that the same input/output actions should perform the same functions with the same behavior.
Note: To learn more in detail about learnability principles, visit this link.
Flexibility principles
Flexibility is the availability of multiple interaction methods between the user and the system. The following are the flexibility principles that support usability.
Dialog initiative: The dialog initiative principle states that
user pre-emptive Initiated by the user system pre-emptive Initiated by the system Multi-threading: The multi-threading principle allows multiple threads or tasks to run simultaneously.
Task migratability: The principle of task migratability refers to efficiently transferring task execution control between the system and the user.
Substitutivity: Substitutivity means that the user should be allowed to substitute equivalent input or output values.
Customizability: Customizability means that the interface should be modifiable by the user or the system.
Note: To learn more in detail about flexibility principles, visit this link.
Robustness principles
Robustness is the ability of an interface to aid the successful accomplishment and evaluation of tasks. Explained below are the principles that concern robustness.
Observability: Observability refers to the ability of users to evaluate a system’s internal state from the information displayed on the interface.
Recoverability: The principle of recoverability concerns the ability of users to reverse the effect of errors.
Responsiveness: Responsiveness refers to the response time taken by the system to communicate with the user.
Task conformance: Task conformance deals with the degree of support the system offers for task completion.
Note: To learn more in detail about robustness principles, visit this link.
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