Comparison between the reference and the entire CSP samples. Top panel: redshift distribution of CSP-I + CSP-II (empty bars) and the 50 SNe Ia comprising our reference sample (orange bars). Bottom panel: s_BV distribution of SNe Ia from CSP-I + CSP-II (empty bars) labelled as ‘normal’ and the reference sample (orange bars). The values of s_BV were obtained by fitting the SNe with SNooPy using the max_model model. Only the ‘normal’ SNe are shown in this case as SNooPy mainly provides templates for these objects and not other types.