Idealized observations: steepness parameter s for the 93 clusters from the Magneticum Pathfinder simulations as a function of the true r₅₀₀. The left panel shows the results for the fits with MBProj2; the right panel shows the results for the hydrostatic mass according to theory. Both panels show the true values for comparison. We do not plot any uncertainties for s, as these are hard to determine because the uncertainties of the fitted values of M₅₀₀ and M₂₀₀ are correlated.