In Figure we plot the ratio between electrical conductivity and absorption coefficient as a function of film composition, to obtain a simple but widely used figure of merit for transparent conductors. In general, slightly P-poor compositions are beneficial for both conductivity and transparency. On the other hand, increasing the Cu/Ca ratio has a beneficial effect on the conductivity but a detrimental effect on the absorption coefficient. Because the former varies over a broader range than the latter, figures of merit are highest (0.005 Ω -1 ) in the Cu-rich region of the diagram. For comparison, the best n-type TCMs have record figures of merit between 1 Ω -1 and 10 Ω -1 75 and p-type CuI has reached 0.02 Ω -1 . If absorption coefficients closer to our computational predictions could be achieved by, e.g., an improved growth process, the figure of merit of CaCuP could potentially reach some of the highest values known for a p-type TCM.