Gas outer radii of our models (R_CO, 90%) compared to observations. The colors correspond to the α_visc of the model. The black open diamonds show observed gas outer radii in Lupus (Ansdell et al. 2018) and the purple open squares denote observed gas outer radii in Upper Sco (Barenfeld et al. 2017). The Upper Sco outer radii shown are 90% outer radii, calculated from their fit to the observed ¹²CO intensity. The top and bottom panels split models and observations based on stellar mass. The sources with M_* ≤ 0.66 M_⊙ are compared to models with M_* = 0.32 M_⊙; those with M_* > 0.66 M_⊙ are compared to models with M_* = 1.0 M_⊙. Only panels for M_* = 0.32 and 1.0 M_⊙ are shown because the sample of observations considered in this work does not contain any objects with M_* ~ 0.1 M_⊙.