  The determination of atmospheric parameters is the first and most fundamental
step in the analysis of a stellar spectrum. Current and forthcoming surveys
involve samples of up to several million stars, and therefore fully automated
approaches are required to handle not just data reduction but also the
analysis, and in particular the determination of atmospheric parameters. We
propose that a successful methodology needs, at the very least, to pass a
series of consistency tests that we dub the 'four-step program'. This and
related issues are discussed in some detail in the context of the massive data
set to be obtained with the Radial Velocity Spectrometer onboard Gaia
