Upper panels: results from a Monte-Carlo simulation where one star is drawn from the Galactic and LMC samples per SpT bin. Probability distributions for the T_eff of three representative SpT bins and for the overall slope of the calibration are shown in the left- and right-hand panels. Lower two panels: two possible SpT – T_eff relations arising from the simulations (employing the same symbols as in Fig. 1), highlighting the potential consequences of drawing conclusions from small samples.