Fluorescent lamp ballasts are subject to DOE appliance standards and rulemaking. But currently, only ballasts for older fluorescent lamp types, such as T-12 lamps are subject to minimum efficacy limits. The majority of fluorescent lamps now being shipped (T-8 and T-5 types) type are operated by ballasts that will not be subject to DOE rule until 2011. The metric used by DOE for characterizing the electrical efficiency of the fluorescent lamp-ballast system is called Ballast Efficacy Factor (BEF). Because BEF is not normalized, it is of limited utility for rulemaking and is useless for procurement. But by normalizing BEF to the total lamp power, I have transformed BEF into a useful metric: Relative System Efficiency (RSE). RSE can be used to unambiguously determining the electrical efficiency of most fluorescent lamp ballast systems. RSE can also be used to characterize the overall efficiency of the ballast industry, somewhat similar to CAF√â limits for automobiles. In this seminar, I will present the results of an analysis, which applied RSE to a database of over 4,200 fluorescent lamp-ballast systems representing a broad cross section of currently available fluorescent lamps. I demonstrate that RSE can be reliably and predictably applied to broad classes of ballasts. I use these data to accurately characterize the current technical capability of the fluorescent ballast industry in the US. Finally, I show how to use RSE to make informed ballast purchasing decisions that are guaranteed to be "best-of-class". Relative System Efficiency has all the positive attributes required of a practical efficiency metric - robustness, generality, transparency and parsimony - without any of the shortcomings that beset other methods. If RSE were to be adopted nationally not just for rulemaking but for procurement of fluorescent ballasts, specifiers could purchase the most electrically efficient ballasts, with confidence, regardless of other non-electrical details of the lighting.