These Ñ2 provide a single value that can be used in conjunction with the qualitative analysis of the N2 to assess the impact of differences in the size of the scattering phase space on the phonon linewidths/lifetimes. This analysis allows us to discuss the τ CRTA in terms of the strength of the interactions between phonons -anharmonicity in this model -and the size of the scattering phase space enabled by the shape of the phonon spectrum. Systems with a short τ CRTA may show strong phonon-phonon interactions (large P) and/or a large phase space (large Ñ2 ). Conversely, systems with long averaged lifetimes could show weak anharmonicity (small P) and/or a small phase space (small Ñ2 ).