Before homogenisation and after – initial method-specific systematic differences can be homogenised away if one has many methods available in a single study. The three top panels present results from specific nodes (see Sect. 9 for detail), while the lower panel shows the outcome of homogenisation, further colour-coded by [Fe/H] to make clear the dispersion is now real astrophysical dispersion. The systematic effects apparent in the top three panels have been substantially reduced.