The development of the single substrate technique presents a realistic possibility of utilising electrochemical noise measurement for on-site evaluations of corrosion behaviour. A theoretical model was developed to further understand the effects of reference electrodes on the acquired data to increase confidence in the technique. The model demonstrates that the reference electrodes can have a significant impact on the measurements, resulting in erroneous values if the reference electrodes are not selected carefully. Furthermore, the derived equations elucidate how to limit/remove such influence, facilitating accurate application of the single substrate technique on bare metal and coated substrates both in laboratories and in the field. (C) 2019 Elsevier Ltd. All rights reserved.