The Advanced Isoconversional (AIC) method involves minimization of a function which uses conversion data at a minimum of three heating rates to determine an activation energy (E-a) at different values of conversion (alpha). Reactions that can be described by a single model give an E-a which is independent of alpha, while reactions which are described by more than one model give an E-a which varies with alpha. Shifts in the conversion curves due to error can lead to E-a vs. alpha trends which falsely indicate, or mask, true multi-model kinetics. It was found that the minimum value obtained during optimization of what we call the 'Optimization Indicator' (Omega) can indicate whether trends in E-a vs. alpha are likely to be error-derived in the case of single-model reactions or artifacts in the case of multi-model reactions. E-a and Omega for the calcination of CaCO3 are used to demonstrate the experimental application of this new diagnostic. Crown Copyright (C) 2016 Published by Elsevier B.V. All rights reserved.