Title: IZI: A Bayesian Approach towards Measuring the Physical Conditions of Ionized Star 
Forming Regions.

Abstract:
The metallicity of the ISM plays a fundamental role in star formation. Among other things it 
affects the dust-to-gas ratio, the formation of molecular gas, the emission properties of galaxies, 
and the Xco factor. Reliable measurements of metallicities in HII regions are challenged by large 
systematic uncertainties in the plethora of emission line diagnostics available in the literature. I 
will present a new method (IZI, Blanc et al. 2014) to measure the physical properties 
(metallicity, ionization parameter) of ionized nebulae using a Bayesian approach that overcomes 
many of the problems affecting strong emission line diagnostics. I will talk about the difficulties 
of measuring reliable chemical abundances in ionized gas and will discuss applications of this 
method to IFU spectroscopic observations of nearby galaxies from VENGA, MANGA, and 
MUSE.