Comparison of the second-order S₂ CWST coefficients used as a measure of non-Gaussianity. The S₂ coefficients of E maps normalized by S₁ are plotted vs scales J₁ and J₂. The data are ordered by J1 values and for each J1 for increasing J2. The plot compares S₂/S₁ ratios for a Gaussian map in purple, the PySM model in yellow, and the model of Vansyngel et al. (2017) and the FoCUS map with a dashed black line. All data values are normalised by those of the FoCUS map. The two blue curves shows the uncertainty (±1σ) on the S₂/S₁ ratio estimated from simulations.