Chemical and age distribution of stars from spectroscopic surveys. Top row and bottom left panel: decomposition of the chemistry–age distribution of stars from Delgado Mena et al. (2017) with ages by Haywood et al. (in prep.) Top row and bottom left panel: stars are coloured according to whether they are part of the inner or outer disc. Several young alpha-rich stars (Haywood et al. 2013) shown in blue are removed from the sample. Bottom right panel: distribution of inner disc stars taken from APOGEE, with the inner disc stars from Adibekyan et al. (2012) and Delgado Mena et al. (2017) plotted as white points.