Relation between UV slope and stellar metallicity for VANDELS galaxies. The average relation from the two indexes (1501 and 1719 Å) is drawn with black squares, while the pale colored squares represent the underlying metallicities from single absorption features. Horizontal bars associated with each of the three data points indicate the range of β slopes of galaxies in the same bin. The relation obtained from combining the best-fit MZR and the M_*–β relation is highlighted with a cyan dashed line and cyan 1σ uncertainty area. On the top x-axis, A₁₆₀₀ is shown for comparison purposes, as determined from the β–A₁₆₀₀ conversion of Meurer et al. (1999). We warn the reader that this conversion may also depend, at a second order, on the metallicity itself.