Comparison between our estimate of effective temperatures (•), and the values we obtained from available Vizier catalogues, for PolarBase spectra. The latter collections are represented as classical boxplots. Objects we studied are listed along the horizontal axis. The number of values found among all Vizier catalogues are presented on a horizontal line around T_eff ~ 4000 K. The horizontal bar inside each box indicates the median (Q₂ value), while each box extends from first quartile, Q₁, to third quartile Q₃. Extreme values, still within a 1.5 times the interquartile range away from either Q₁ or Q₃, are connected to the box with dashed lines. Outliers are denoted by a “+” symbol.