An increasing activity of reactant intermediates with increasing overpotential (in absolute terms) means the Tafel slope will be lower than expected in the constant-coverage case and vice versa (Eq. 16c-d). Consequently, the Tafel slope reflects the product of the number of electrons transferred times the associated symmetry factor for the rds only in the constant-coverage-Tafel region. In the varying-coverage-Tafel region, where its value may also be constant, it also contains the influence of the varying coverage. It is therefore not possible to derive any mechanistic conclusions from the Tafel slope alone without taking into consideration the overpotential dependence of the activity of the intermediates.