 The proposed equation for estimating the Lorentz number, L, from the thermo-power, S, is an improvement over the current method of using a constant value when detailed band structure and scattering mechanism is unknown. This equation provides a more accurate estimate of the lattice thermo-conductivity, CAP-L, which is important for understanding heat transfer in materials. This article was offered by Hyunsik Kim, Zachary M. Gibbs, Inglutang, and others.