To that end, this report provides a synopsis of poverty measurement in the United States, focusing on the following: 
the official measure of poverty, which is used to obtain official counts and percentages of the poor; the Supplemental Poverty Measure, which is used for research purposes only and was developed to improve upon some limitations of the official measure; and the Health and Human Services (HHS) poverty guidelines, which are used in administering programs for low-income persons but not to measure the poor population. Poverty measures convey the number or percentage of people falling below given income amounts, which are intended to represent a level of economic privation and are computed using some factually based measurement of basic needs. A family's income is compared against a dollar amount representing some measure of need, called a threshold , which typically varies by a family's size and composition. Those with family income less than the threshold are considered to be "in poverty," or poor; those with incomes greater than or equal to the threshold are not considered to be in poverty. All members of the same family have the same poverty status. They are financial measures, and do not directly capture the physical, mental, or social effects of being poor. Poverty Measures Are Not the Same as Sufficiency Measures

Even within their focus on financial resources, the purpose of these poverty measures when they were developed was to accurately measure economic privation rather than to describe the full complement of resources a person or family needs to be self-sufficient. Poverty Measures Are Estimates Based on Survey Data

Poverty data are obtained from surveys, and are therefore estimates that have margins of error. Poverty estimates derived from different data sources—even those using the same definition of poverty—will almost always differ. The Supplemental Poverty Measure

There has been broad agreement among poverty scholars that the limitations noted above represent serious drawbacks to the official poverty measure, and also that fixing them has not been a straightforward task. In 2009, the Office of Management and Budget (OMB) convened an Interagency Technical Working Group (ITWG) to consolidate the research and propose a single Supplemental Poverty Measure, which would be used for research purposes only. Legal Authority for Poverty Measurement

Neither the official poverty measure nor the Supplemental Poverty Measure was established in statute. OMB, the successor agency to the Bureau of the Budget, issued Statistical Policy Directive 14 in 1978, reconfirming the measure as official and directing federal agencies to use it for statistical purposes. The directive explicitly stated that the measure was not developed for administrative purposes, and allowed for other measures of poverty to be developed, as long as the data for those measures were distinguished from the official series. Unlike the measures discussed in this report, the poverty guidelines are not used to count the number of people or families in poverty. Simplification of the Poverty Thresholds for Administrative Use

As explained earlier, the official poverty thresholds were based on empirical measures of dietary need, the amount that a family in economic distress might need to spend on food in order to attempt to meet its dietary needs, and the spending patterns of families across the income distribution (to determine what percentage of an average family's budget was spent on food).
Poverty measures convey the number or percentage of people falling below given income amounts, which are intended to represent a level of economic privation and are computed using some factually based measurement of basic needs. The poverty measures discussed in this report—the official U.S. poverty measure and the research Supplemental Poverty Measure—focus on financial resources. A family's income is compared against a dollar amount representing some measure of need, called a threshold, which typically varies by family size and composition. Those with family income less than the threshold are considered to be "in poverty," or poor; those with incomes greater than or equal to the threshold are not considered to be in poverty. All members of the same family have the same poverty status.
The poverty measures discussed here are financial measures; they do not directly capture the physical, mental, or social effects of being poor. They were developed to accurately measure economic privation rather than to describe the full complement of resources a person or family needs to be self-sufficient.
Poverty data are obtained from surveys, and are therefore estimates that have margins of error. Poverty estimates derived from different data sources—even those using the same definition of poverty—will almost always differ.
The official poverty thresholds were developed in the early 1960s, and were based on empirical measures of dietary need, on the amount that a family in economic distress might need to spend on food to attempt to meet its dietary needs, and on the spending patterns of families across the income distribution. This information was used to determine what percentage of an average family's budget was spent on food, and in turn, to compute the amounts representing total family income.
There has been broad agreement among poverty scholars that the official poverty measure has serious limitations, and decades of research were undertaken to address them. In 2009, an interagency technical working group, convened under the auspices of the Office of Management and Budget (OMB), put forth the Supplemental Poverty Measure to consolidate the research and emphasize not only sound concepts and methodology in the measure's development, but also practicality in the measure's maintenance, computation, and usage. The Supplemental Poverty Measure was not intended to replace the official measure, and it was expected that refinement of the Supplemental Poverty Measure's methodology and data sources would continue.
Neither the official poverty measure nor the Supplemental Poverty Measure was established in statute. The Bureau of the Budget and its successor agency, OMB, directed federal agencies to use the official measure for statistical purposes. The directive explicitly stated that the measure was not developed for administrative purposes, and allowed for other measures of poverty to be developed, as long as the data for those measures were distinguished from the official series.
For administrative uses, such as determining whether an individual or family is eligible for assistance from a program, a different set of dollar amounts called poverty guidelines is used. Poverty guidelines are different from the official poverty thresholds, are published by the Department of Health and Human Services, and are not used to count the poverty population. However, any program that relies on counts of the poverty population, such as for formula grants, uses the official poverty thresholds and not the guidelines.