Why DC resistance measurement results will be different when the connection direction of DUT is reversed?

The temperature difference between two different metals creates a voltage across the junction. It is so called thermoelectric effect. And the junction voltage makes the measurement results higher or lower than the real value by two reversed connection directions with DUT. Chroma 16502 Milliohm Meter provides special pulsed test mode in addition to general DC test mode, for effectively reducing the measurement error caused by thermoelectric effect.