Inference on the Einstein radius and density slope of a subset of lenses obtained assuming flat priors on all of the lens model parameters. The black bars indicate the 68% credible region. Circles are true values of θ_Ein and γ of the lenses and are colour-coded according to the image asymmetry parameter ξ_asymm, defined in Eq. (30). The grey dotted lines connect the true values to the corresponding measurement.