Given the relatively small anisotropy in the predicted electrical properties and κ latt , we predict that the ZT are relatively isotropic (Figs S13-S15, ESI † ). In CTO, the ZT is largest along the a direction and smallest along the b direction, at ∼ 5 -10% larger and 10-15% smaller than the average value, respectively, depending on the temperature. This is due to the anisotropy in the electrical conductivity and power factor. In STO, the ZT is largest along the equivalent a and b directions, at 6-8% larger than the average, and smallest along the c direction, at ∼ 10 -15% smaller. In this case, the anisotropy is largely due to the lattice thermal conductivity. In BTO, on the other hand, the isotropic electrical and thermal transport combine to produce a relatively isotropic ZT , which varies by a more modest ∼ 1 -5% and is largest along the a/b directons.