Comparison between the PWZ parameters obtained with our baseline sample (F+1O pulsators, using [Fe/H], black squares) and those obtained: (i) using a pure σ-clipping algorithm (red circles); (ii) using only F-mode pulsators with [Fe/H] as abundance indicator (blue triangles); (iii) using F+1O pulsators with the total metallicity [M/H] as abundance indicator (green diamonds); and (iv) using only objects with G < 12.5 mag (violet stars). The shaded area comprises the range −0.4 < γ < −0.2 mag/dex, where most of the recent literature results are located. The units of α,  β,  γ,  ϵ and of their uncertainties are mag, mag/dex, mag/dex, and mas, respectively.