This invention describes the addition of mechanical reference members (MRM) to MEMS gyroscopes and accelerometers in order to enable the measurement of their scale factor and bias characteristics. The measurements can be made prior to or during operation of the instruments. This approach is attractive since MEMS devices are subject to drift of these characteristics with time, with the environment and with application conditions. The mechanical reference members are used to provide a rotation rate reference for the gyroscopes and an acceleration reference for the accelerometers.