Since 2003, the National Center for Education Statistics (NCES) has compared each state's standard for proficient performance in reading and mathematics by mapping each state's standard onto the appropriate National Assessment of Educational Progress (NAEP) scale. The results of those comparisons have been provided in three earlier reports, using state data for reading and mathematics at grades 4 and 8 from 2003, 2005, and 2007. This report provides highlights of applying the methodology for mapping state proficiency standards onto the NAEP scales using state data from the 2008-09 academic year and the 2009 NAEP grade 4 and 8 reading and mathematics assessments. The analyses summarized in this report address the following questions: (1) How do states' 2009 standards for proficient performance compare with one another when mapped onto the NAEP scale?; (2) How do the 2009 NAEP scale equivalents of state proficiency standards compare with those estimated for 2007 and 2005?; and (3) Does NAEP corroborate a state's changes in the proportion of the students meeting the state's standard for proficiency from 2007 to 2009? From 2005 to 2009? Limitations in the 2003 state assessment data (e.g., many states did not test grades 4 and 8 as NAEP) precluded a 2003 to 2009 comparison analysis. Appended are: (1) NAEP scale equivalent scores for state reading proficiency standards at grades 4 and 8 in 2009, and their differences from the 2005 and 2007 estimates of the same standards, by state; (2) NAEP scale equivalent scores for state mathematics proficiency standards at grades 4 and 8 in 2009, and their differences from the 2005 and 2007 estimates of the same standards, by state; (3) Direction of change in the estimated NAEP scale equivalent scores of state reading proficiency standards for the states that did not make significant changes in their assessments, by grade and comparison result: 2007 to 2009; and (4) Direction of change in the estimated NAEP scale equivalent scores of state mathematics proficiency standards for the states that did not make significant changes in their assessments, by grade and comparison result: 2007 to 2009. (Contains 20 figures and 7 tables.)