While AMSET correctly predicts the relative importance of the different scattering mechanisms, the low concentration regime phonon-limited mobility predicted by AMSET and the IBTE method varies by a factor of 4. As POP scattering is the primary mobility-limiting mechanism in this material at low carrier concentrations, this overestimation of the scattering rate results in mobility values that are lower than those reported in the experimental literature (notably the single crystal result from Chen et al.) . One way to explain this is the inelastic treatment of POP in AMSET. Indeed, AMSET approximates POP scattering using the self-energy relaxation time approximation (SERTA), which as part of its formalism only considers scattering in the forward direction relative to charge carrier motion. The omission of backward scattering can lead to an underestimation of phonon-limited mobility, the extent of which varies between materials depending on the complexity of the band edge (single band or multi-degenerate), the effective mass, and spin-orbit effects. The comparison between phonon-limited mobility and experimental results can be challenging since most calculations do not consider impurities or defects. While SERTA serves as an approximation of IBTE, it is advisable to prioritize the latter due to its comprehensive nature, even if certain SERTA results appear closer to experimental data. For instance in Si, the computed electron mobility with the two methods fall within the range of experimentally reported mobilities, although the hole mobility is overestimated by both approaches -only when performing simulations using the experimental lattice parameter and fitting the band structure to the experimental hole effective mass is agreement with experimental mobility recovered using the IBTE approach; for SiC the IBTE performs better than the SERTA for electron mobility (SERTA underestimates by around 30%), while they straddle the upper and lower side of experimental results for the hole mobility, respectively; and for GaAs both the implementations provide rather unreliable results, not helped by the large range of experimental mobilities reported. Surveying over 50 materials, Claes et al. show that differences in computed mobility using IBTE and SERTA can reach up to 60%, and that the differences are often particularly large for binary halides with low 𝜔 POP such as NaI, CsI and TlBr. The general trend is that SERTA will, if at all, underestimate phonon-limited mobilities compared to the exact IBTE results. Crucially, it is difficult to predict a priori the severity of the underestimation.