Ratio between CO and dust sizes as a function of various stellar and disk properties. Top left: as a function of the stellar mass of the central object (M_⋆ ). Top right: asa function of the dust size (). Bottom left: as a function of the disk mass, estimated from M_dust and assuming a gas-to-dust ratio of 100. Bottom right: as a function of the CO size (). Following the results of disk evolution models from Trapman et al. (2019), disks with a size ratio above the horizontal threshold cannot be explained without prominent dust evolution.