Evolution of discrepancy measures and rotation parameters in a series of solutions for which the k most discrepant sources have been removed. (a) Discrepancy measure Q_i/n_i for the most discrepant source in the solution. Points are labelled with the name of the source. (b) Total discrepancy measure Q/n as a function of the number of rejected sources. (c) Estimated orientation parameters and (d) spin parameters as functions of the number of rejected sources. Error bars are formal ±1σ uncertainties from the inverse normal matrix, i.e. not adjusted depending on the goodness-of-fit.