is regulated, and how the processes that govern galactic inflows and outflows operate in detail @Dave11a [@Dave11b; @Lilly13].

In addition to the local MZR and its dependence on SFR, the same correlations can be studied in high redshift galaxies in order to probe galaxy formation and evolution in the early universe [@Shapley05; @Erb06; @Maiolino08; @Steidel14; @Zahid14b; @Sanders15]. Furthermore, the correlation between ${\hbox{$M_{\star}$}}$, Z, and SFR in the early universe, and how that relates to the correlations observed in the local universe, constrains how the population of galaxies has evolved over cosmic time [@Zahid14; @Maier14; @Izotov15].

Accurate and precise metallicity measurements are vital to gain physical insights from both local correlations and evolution over cosmic time. The most reliable oxygen abundances are determined with the “direct method”, or “$T_e$ method” [@Dinerstein90]. Under the right conditions, the electron temperature of ionized gas can be directly measured from the temperature sensitive intensity ratios of collisionally excited forbidden lines (e.g. \[\] $\lambda$4363/\[\] $\lambda$5007). As oxygen is one of the primary coolants in the ISM, the temperature is anticorrelated with abundance. The density of the gas can be measured from density sensitive lines (e.g. ${\hbox{[\ion{S}{ii}]~$\lambda$6717/$\lambda$6731}}$). For a given temperature and density the emissivity of a 