The variation of conductance during sorption in a variety of different materials exhibits a similar response. However, the detailed understanding of the surface conduction during adsorption still has to be achieved. A simple theoretical framework is presented here, in which we were able to model adsorption-induced conductance changes and obtain the well-known shape of the characteristics. Our model calculations revealed that the unexpected similarity of the response is the consequence of the dynamic nature of adsorption processes in real systems. (C) 2014 Elsevier B. V. All rights reserved.