Abstract: A method for correcting a measurement of a property of a subsurface material includes: selecting an instrument having a test circuit and a separate sensor, the test circuit configured for generating a test signal having a characteristic that mimics a downhole measurement environment to generate correction information. The sensor is configured for: transmitting a signal into the subsurface material; and receiving a data signal from the subsurface material; wherein the test circuit and the sensor are switchably coupled to an electronics unit of the instrument. The sensor is further configured for: receiving the test signal from the test circuit in the electronics unit; using the electronics unit, measuring at least one output characteristic of the instrument; and applying the correction information to the data signal according to the measured output characteristic.