During the design process, the engineer may want to consider the extent to which changes in system parameters affect the behavior of a system. Ideally, parameter changes due to heat or other causes should not appreciably affect a system's performance. The degree to which changes in system parameters affect system transfer functions, and hence performance, is called sensitivity. A system with zero sensitivity (i.e. changes in the system parameters have no effect on the transfer function) is ideal. The greater the sensitivity, the less desirable is the effect of a parameter change.