Political perspectives on the advisability of state achievement comparisons have changed substantially over the last half-century. As Selden (2004) noted regarding the National Assessment of Educational Progress (NAEP), "[w]hen it began in the 1960s, NAEP specifically was designed "not" to provide comparisons among states. This was done for political reasons, so that the assessment program would be palatable to the educational community and to the states" (p. 195). During the No Child Left Behind Era, state comparisons were complicated by the use of tests and proficiency standards that differed across states. Because of today's Common Core Standards Initiative, state comparisons are once again at the forefront of educational policy discussions. The initiative brings with it both significant opportunities and substantial psychometric challenges.