Control-Display Compatibility

Control-display compatibility is important in human-to-system interface design. It can be defined as the degree to which the function and use of a control and its associated display are unambiguous and immediately apparent to the user. Highly compatible controls and displays result in decreased reaction time, fewer errors, decreased training time, and higher user satisfaction.

To achieve high compatibility, it is important to consider user expectations and experience with similar controls and displays. For example, most users associate turning a rotary knob clockwise with increasing a value and expect the associated display to exhibit this increase. Also, the purpose of the information provided by the display and its associated control must be considered. For instance, the precision needed from a display and the precision that can be achieved with its associated control should match.

Analog displays may be preferable in some conditions where at-a-glance system status is needed and associated controls do not require extreme precision. By contrast, setting course information into a flight management system or setting the trajectory for a satellite requires digital displays and controls to input precise numeric values.

Analog Displays - At-a-glance abnormal condition is obvious.	Digital Displays - Must read each display to detect out of normal condition.