[Fe/H] errors as a function of S/N per pixel for measurements of individual VLT/FLAMES LR8 spectra, consistent with membership in the Sextans dSph and with G < 19.7. The blue squares are stars that do not pass the vdiff criterion and the red star symbols ones that do not pass the EW criterion; some fail on both. The vertical dotted red line indicates S/N = 16 per pixel, the cut that was applied to the final selection of reliable [Fe/H] measurements.