When performing an action the system reports the result of the operation and its status in general.

Context

The user requires system feedback to direct attention to events, which may be out of the visual focus.

Forces

The rationale here is to avoid unnecessary steps to confirm notifications, e.g., by using message boxes, and to avoid irritating audible clues, e.g., using the same audible clues for different types of messages.

Solution

Display the message in the dialog or screen where the action causing the feedback was performed. Use the bottom of the dialog or screen and highlight the message area to clearly indicate the change of the screen. There are several types of messages:

• Information. The system informs the user, e.g., about a completed download.
• Warning. The system informs the user that further action or decision is required before being able to proceed.
• Critical. The system encountered an error and informs the user that the action could not be performed as desired.
• Progress. The system informs the user that something is being processed.

Animated visual clues may serve to attract attention if they take place in the peripheral vision, which is more suited to detecting movement.

Audible clues must be adjusted to the importance of the notification such that the operator is able to distinguish certain types of messages based on the audio signal.

Usability Impact

Operators are more easily able to direct their attention based on visual and audible system feedback.

Safety Impact

This pattern prevents users from being disrupted in their workflow by notifications, which are not safety-relevant.

Sample

The sample shows an example critical error message upon failing to connect to a remote system.