Upper panels: comparison between the parameters recovered with FERRE from our simulations against the true values for the case when all the filters are included. The red curves show a least-squares fit to the data. Bottom panels: histograms of the residuals for each parameter. The red curves correspond to a Gaussian fit to the data, which systematically underestimates the width of the distribution for [Fe/H]; therefore, it is not adopted for the statistics shown in the tables and is discussed in the text. The median offsets of the distributions are 0.03 dex, 6 K, and 0.08 dex for [Fe/H], T_eff, and log  g, respectively. The straight standard deviations are 0.98 dex, 58 K, and 0.67 dex, while those computed with the robust algorithm described in the text are 0.70 dex, 45 K, and 0.57 dex.