Comparison of the different strong-line metallicity diagnostics N2 ([N ii]/Hα), O3N2 ([O iii]/[N ii]), and O3HB ([O iii]/Hβ). Metallicities are derived from the calibrations of Pettini & Pagel (2004; left panel) and Maiolino et al. (2008; center and right panels). Each point represents an individual OSIRIS pixel; data are identical to those in Figure 4. The 1σ scatter measured by Pettini & Pagel (2004) is shown in the lower right of the left-hand panel. Metallicities derived from different methods are generally in agreement, with [O iii]-based metallicities typically 0.15 dex lower than those derived from N2. Metallicity derived using the Maiolino et al. (2008) calibrations are systematically higher by ~0.2 dex compared to Pettini & Pagel (2004).