Through an array of well-controlled synthetic experiments, this work investigates the quality of the aforementioned methods for the selection of 𝜆 in the context of DRT deconvolution and impedance recovery through RR (Figure ). For RR, the analysis of synthetic spectra suggests that GCV and mGCV give 𝜆 values that are the closest to the optimal ones. It is also shown that 𝜆 0 , one of the hyperparameters of the previously developed hierarchical Bayesian method (hyper-𝜆)