Time on Task is not a commonly used usability metric, as it is more focused on efficiency rather than user experience.

The System Usability Scale (SUS) is a widely used questionnaire that measures overall user satisfaction with a product or service.

Task Completion Rate is calculated by dividing the number of tasks completed successfully by the total number of tasks attempted.

Cognitive Walkthrough evaluates the user's mental model of the system to identify potential usability problems.

Error Rate measures the number of errors made by users while performing a task.

Heuristic Evaluation is a method used to identify potential usability problems by evaluating the system against a set of predefined usability heuristics.

Time on Task is calculated by dividing the total time taken to complete a task by the number of users.

The goal of User Experience (UX) Design is to create products that are easy to use and enjoyable, thereby enhancing the overall user experience.

User Satisfaction measures the user's emotional response to a system, such as their level of enjoyment, frustration, or satisfaction.

Think Aloud Protocol is a method used to gather user feedback by asking users to verbalize their thoughts and actions while performing a task.

Task Completion Rate is calculated by dividing the number of tasks completed successfully by the total number of tasks attempted.

Focus Group is a method used to gather user feedback by conducting a discussion with a small group of users.

Interaction Count measures the number of times a user has to interact with the system to complete a task.

The goal of Usability Testing is to identify potential usability problems by observing users while they interact with the system.

Error Rate is calculated by dividing the number of errors made by users by the total number of tasks attempted.