star, while the upper limit of [\[C/Fe\]]{} $= +0.10$ for the star in the right panel implies that it is a C-normal star.

Validation of the \[C/Fe\] Determinations
=========================================

Star-by-star Comparison with High-resolution Abundance Analysis
---------------------------------------------------------------

Having developed a new technique for the estimation of \[C/Fe\], we now seek to calibrate and validate this method with external measurements. Although this can be carried out by comparison with the overall behavior of a sample of stars, it is preferable to compare star-by-star (ideally against different sources of external measurements), in order to quantify possible systematic offsets (and optionally remove them), as well as to determine the likely external errors associated with the estimate. For these purposes, we employ a set of SDSS/SEGUE stars with available high-resolution spectroscopy analyzed by Aoki et al. (2008, 2013), Spite et al. (2013), and Yong et al. (2013). Table \[tab:hiressam\] lists the stars used to validate our technique, along with their adopted atmospheric parameters from the high-resolution spectra, and those used by the SSPP.

The majority of the stars in Table \[tab:hiressam\] were analyzed by Aoki et al. (2008, 2013), who obtained high-dispersion ($R\sim36,000$) spectra with the Subaru Telescope High Dispersion Spectrograph (Noguchi et al. 2002). 