  SDSS-IV APOGEE-2, GALAH and Gaia-ESO are high resolution, ground-based,
multi-object spectroscopic surveys providing fundamental stellar atmospheric
parameters and multiple elemental abundance ratios for hundreds of thousands of
stars of the Milky Way. We undertake a comparison between the most recent data
releases of these surveys to investigate the accuracy and precision of derived
parameters by placing the abundances on an absolute scale. We discuss the
correlations in parameter and abundance differences as a function of main
parameters. Uncovering the variants provides a basis to on-going efforts of
future sky surveys. Quality samples from the APOGEE-GALAH, APOGEE-GES and
GALAH-GES overlapping catalogs are collected. We investigate the mean variants
between the surveys, and linear trends are also investigated. We compare the
slope of correlations and mean differences with the reported uncertainties. The
average and scatter of vrad, Teff, log g, [M/H] and vmicro, along with numerous
species of elemental abundances in the combined catalogs show that in general
there is a good agreement between the surveys. We find large radial velocity
scatters ranging from 1.3 km/s to 4.4 km/s when comparing the three surveys. We
observe weak trends: e.g. in $\Delta$Teff vs. $\Delta$log g for the APOGEE-GES
stars, and a clear correlation in the vmicro-$\Delta$vmicro planes in the
APOGEE-GALAH common sample. For [$\alpha$/H], [Ti/H] (APOGEE-GALAH giants) and
[Al/H] (APOGEE-GALAH dwarfs) potential strong correlations are discovered as a
function of the differences in the main atmospheric parameters, and we find
weak trends for other elements. In general we find good agreement between the
three surveys within their respective uncertainties. However, there are certain
regimes in which strong variants exist, which we discuss. There are still
offsets larger than 0.1 dex in the absolute abundance scales.
