The National Assessment Governing Board (NAGB) is considering creating a National Assessment of Educational Progress (NAEP) for world history education. On the surface, a national assessment in world history appears to be a sensible and essentially unproblematic decision. However, problems lurk below the surface challenging the creation of a national assessment in world history. First, many states spread world history throughout and across grade levels placing a sizable portion of world history content in the middle school years or in the first years of high school. One set of issues involves assessing 12th grade students on content they had in the 9th or 10th grade, or even earlier. Doing this could mean that educators would simply get another assessment that shows that United States students do not know much about the past. A second challenge--maybe even greater for developing a common national assessment--involves the variations in the type of world history that United States students encounter in their schools. In this essay, the authors present a picture of the state of world history education to illuminate the challenges NAGB faces in constructing a NAEP world history framework. The authors then provide a brief overview of the growth of world history education, including the AP World History exam. Based on a review of state standards and the AP World History program, the authors also describe what they see as four distinctive patterns to world history education. Finally, given NAGB's charge to assess instruction across the nation without defining it for the nation, the authors discuss options for developing the NAEP world history framework in the midst of such diversity, and the possible consequences of each option. (Contains 10 charts and 38 notes.)