Differences between stellar parameters from the literature (interquartile mean (IQM) values taken from Soubiran et al. 2010) and the stellar parameters derived in this study versus the literature parameters – top: effective temperatures; middle: surface gravities; bottom: metallicities. The circles correspond to stars with homogeneous stellar parameters, crosses (triangles) denote stars whose gravities (metallicities) were adopted from the literature. The error bars are given by Eq. (3), PARAM (see text) and Eq. (6)for the three respective stellar parameters. The jagged line indicates the uncertainty of the literature values (IQR/1.35).