The supplemental rate adds complexity and context to the official poverty rate in that it takes into account benefits, such as tax credits, and differences in necessary expenses, such as whether or not a family is renting or paying a mortgage.
The impact of the adjustments vary. In 13 states the supplemental poverty rate was higher than the official poverty rate, while in 28 states it was lower, the Census Bureau reported.
By comparison, the official poverty rate for 2012 is 15 percent.
Census Bureau economist Kathleen Short said the goal of the second measure is to "gauge the effectiveness of tax credits and transfers in alleviating poverty."
By example, the supplemental poverty measure deducts out-of-pocket medical expenses, child care and work related expenses, income and payroll taxes from incomes.
Each of these exacts its own effect on the poverty rate. "Without accounting for medical out-of-pocket expenses, the number of people living below the poverty line would have been 39.2 million rather than the 49.7 million people classified as poor with the supplemental poverty measure," the bureau said.