Abstract: A method for deriving information for setting a fitting parameter of a cochlear implant, wherein the cochlear implant includes an electrode array having a plurality of stimulating electrode contacts. The method includes modelling an interface between an electrode contact of the electrode array and a cochlear tissue as a corresponding electrical circuit comprising a resistive component representative of Faradaic resistance at the interface; determining at least an impedance value corresponding to the resistive component; obtaining an indication of a value of a fitting parameter for the electrode contact by mapping the determined impedance value to a mathematical model relating the fitting parameter to the impedance.