Impact of different choices for the PE corrections on 1-dimensional posterior distributions of cosmological parameters from Planck TT,TE,EE+lowE. The red lines show results when leaving the PE parameters free to vary independently for EE and TE, while the grey lines assume coupled parameters for the EE and TE spectra. The green lines show results obtained when fixing the polarization efficiencies in the spectrum-based approach to the values given by Eq. (47). Finally the black lines show results obtained when fixing the polar efficiencies in the map-based, baseline case (Eq. (45)). The solid lines show results for the ΛCDM case, while the dotted ones show results for the ΛCDM+A_L model. This plot demonstrates that the cosmological parameters in the ΛCDM case are robust to changes in the PE-correction model.