Information Rate

The amount of information successfully communicated per unit of time through a communication channel or interface, measured in bits per second. In HCI and assistive technology evaluation, information rate quantifies how efficiently a user can convey commands or intentions through an interface by measuring the reduction in uncertainty (entropy) at the receiver divided by the time taken. A higher information rate indicates a more efficient interface. Information rate accounts for both the speed of input actions and the accuracy of the system's recognition, making it a more comprehensive metric than speed or accuracy alone for comparing interface designs.