This technical brief examines the current alignment between the New Mexico Standards Based Assessment (NMSBA) standards and the 2009 National Assessment of Educational Progress (NAEP) mathematics framework. It looks at the extent to which current state assessment standards cover the content on which 2009 NAEP assessments will be based. Applying the methodology used by Regional Educational Laboratory Southwest in 2007 in a similar study that examined the alignment of New Mexico science standards with the 2009 NAEP, this study presents results for areas of full alignment, partial alignment, nonalignment, and areas where the NMSBA assessment standards go beyond the NAEP standards. The study finds that 92 percent of NAEP grade 4, 94 percent of NAEP grade 8, and 80 percent of NAEP grade 12 assessment standards (aligned with current NMSBA assessment standards) and 77 percent of NAEP grade 12 assessment standards (aligned with proposed NMSBA assessment standards) are either fully or partially addressed by the NMSBA assessment standards. The study analyzes the alignment of the NMSBA and 2009 NAEP mathematics assessment standards. It does not analyze individual items or the alignment of state standards with the NMSBA assessment items. The study does not make specific recommendations about whether a state should close gaps in alignment to NAEP--a decision for state policymakers. Revising assessments requires substantial time and resources, so policymakers considering such revisions need to weigh the costs of such changes and the benefits they believe such changes will bring to students. (Contains 15 tables, 4 figures and 2 notes.)