Part of CPSP's poverty measurement research, Poverty in the 50 States: Long Term Trends and the Role of Social Policies presents the first estimates of state-level trends in poverty using a historical version of the Census Bureau and the Bureau of Labor Statistics’ Supplemental Poverty Measure (SPM). The SPM provides a more accurate measure of poverty than the Official Poverty Measure (OPM), which has been in use since the 1960s. CPSP developed individual state fact sheets and compiled all fact sheets into a comprehensive chartbook.