Internal validation using Monte Carlo simulations to assess the recovery of the polarization angle of the 30, 44, and 70 GHz channels. In these simulations, point sources spanning the full range of polarization angles were injected into the Q and U maps with 50 different polarized flux density values, starting at 0.2 Jy and increasing with a step size of 0.1 Jy. The difference between the recovered and true angles is plotted against the true polarized flux density. Here we see there are no biases in the recovery of the polarization angle, although obviously the uncertainty increases for fainter sources.