Accuracy measured through the standard deviation of the difference between the true output parameters and those predicted by IGM+z. The top row shows the accuracy in rest frame wavelength of Lyα, the outflow expansion velocity and the outflow neutral hydrogen column density from left to right. In the bottom row we show the accuracy for the intrinsic equivalent width and width before entering into the ISM and $f_{\text{esc}}^{4\stackrel{\circ }{\mathrm{A}}}$ from left to right. This is computed for 6 values of W_g and Δλ_Pix and 4 of S/N_p, i.e., 24 mocks of 10000 Lyα line profiles. These are split by their true $f_{\text{esc}}^{4\stackrel{\circ }{\mathrm{A}}}$ in 6 bins. The color of each cell is shown in darker for smaller values (better accuracy).