yield with decreasing mass [e.g., @dekel86]. However, @dalcanton07 emphasizes the importance of star formation efficiency as outflows are an insufficient regulator in the absence of depressed star formation. In addition, Dalcanton’s calculations show that low effective yields cannot be due to gas infall. Alternatively, @koppen07 showed that the M-Z relationship may be observed naturally if a SFR-dependent, and therefore mass-dependent, stellar initial mass function (IMF) is assumed. Clearly a better understanding of the mass-metallicity relationship at low-luminosity remains important to determine how galaxies evolve [e.g., see discussion in @moustakas12 and references therein]. In addition, a well defined low-luminosity M-Z relationship will provide clues to the source of its measurable scatter. While observational errors play a role, one or more physical processes may be responsible for the remainder. Suggestions for the scatter include variations in the star formation history [e.g., recent starbursts, @contini02], variations in stellar surface mass density [@ellison08], inflow of metal poor gas, perhaps triggered by interactions [@jlee2004], and variations in local galaxy density [e.g., @cooper08 and references therein]. As astronomers examine the interrelationship between chemical abundance measurements, star formation, gas accretion, and gas outflow by measuring the evolution of the M-Z relationship, a secure M-Z relationship for the 