Distribution of the mass biases, (1 − b_HE, X), on the left, and (1 − b_HE, SZ), on the right, before (top panels) and after (bottom panels) the corrections expressed respectively in Eqs. (16) and (17). The empty histograms show the overall distribution of all the 175 clusters, the filled histograms are restricted to the 97 well-fitted objects. The parameters characterizing the histograms are reported in Table 2.