An accurate assessment of the stringency of state emission goals under EPA’s proposed Clean Power Plan compares state emission goals to adjusted state emission rates that incorporate known and reasonably foreseeable measures that will affect CO2 emissions from existing power plants. These adjusted emission rates may include projections of actual generation and emissions, which may differ from the building block assumptions used in EPA’s Clean Power Plan. In addition, projections in performance levels can reflect the emission and generation impacts that compliance measures will have on the electricity system. Consideration of these impacts can lead to a more accurate comparison of a state’s projected CO2 performance level to its final emission goal under the Clean Power Plan and result in state plans that are optimized for the degree of required emission reduction.