The inverse of the P are plotted against the averaged lifetimes τ CRTA at 300 K in Fig. . If the differences in the τ CRTA are mainly determined by differences in the interaction strengths, we would expect a good linear correlation. The three Fm 3m do show a very good linear correlation (R 2 ≈ 1), which suggests anharmonicity predominantly accounts for the differences in the lifetimes. While it appears that this correlation could be extended to the two R3m phases and Cmcm SnSe, the correlation was found not to be statistically significant when tested. On the other hand, the four Pnma phases form a discrete cluster that clearly does not fall on the trendline set by the other six systems. Compared to the other structures, the lifetimes are considerably shorter than would be expected given the weaker P, indicating that the lifetimes of the Pnma phases are strongly influenced by the size of the scattering phase space.