Degree of integration

The degree of integration measures the ratio between the number of degrees of freedom (DOF) provided by the logical

part of the instrument and the number of DOFs captured by the input device. This term comes from the notion of

integral tasks: some tasks are performed more efficiently when the various DOFs are controlled simultaneously with a single device. A scrollbar is a 1D instrument controlled by a 2D mouse, therefore its degree of integration is 1/2. The degree of integration can be larger than 1: controlling 3 rotation angles with a 2D mouse has a degree of integration of 3/2. This property can be used to compare instruments that perform similar operations. For example, panning over a document can be achieved with two scrollbars or a 2D panner. The latter has a degree of integration of 1 and is therefore more efficient than two scrollbars, which have a degree of integration of 1/2 and incur additional activation costs.