The Patient Protection and Affordable Care Act (PPACA) requires health insurance carriers to meet medical loss ratio (MLR) requirements on a state-by-state basis starting in 2011. This leaves insurers with a fairly short time frame in which to learn the intricacies of MLR calculations. Because specifications and interpretations are also likely to evolve over time, health plans will need to keep abreast of any regulatory changes and should consider performing annual operational audits that document their compliance efforts.