It is shown that the dielectric relaxation in barrier coatings may be interpreted in terms of a 'two-step' continuous time random walk in one dimension. This was proved by comparison of the results using a normalised constant phase element whereby the evaluated coating parameters are in good agreement using both models. An analysis of the frequency dependence of the evaluated coating parameters suggests that the coating capacity calculated by means of a Young-Goehr impedance can be considered to represent a kind of border value for the normalised CPE-as well as for the random walk model. Comparing the results of electrochemical impedance spectroscopy and relaxation voltammetry one has to take into account the frequency dependence of the calculated coating parameters. Furthermore, an example is given which demonstrates that one can obtain equal results choosing the same frequency range and the same model using both techniques.