Interaction principles and design recommendations.
The dialogue is suitable for a task when it supports the user in the effective and efficient completion of the task.
The dialogue is self-descriptive when each dialogue step is immediately comprehensible through feedback from the system or is explained to the user on request.
The dialogue is controllable when the user is able to initiate and control the direction and pace of the interaction until the point at which the goal has been met.
The dialogue conforms with user expectations when it is consistent and corresponds to the user characteristics, such as task knowledge, education, experience, and to commonly accepted conventions.
The dialogue is error tolerant if despite evident errors in input, the intended result may be achieved with either no or minimal action by the user.
The dialogue is capable of individualization when the interface software can be modified to suit the task needs, individual preferences, and skills of the user.
The dialogue is suitable for learning when it supports and guides the user in learning to use the system.