As part of the March 1979 Current Population Survey, the Bureau of the Census conducted an experiment in an effort to improve the reporting of income. For the purpose of the experiment, the full CPS sample was divided into two samples—each representative of the U.S. population. An experimental questionnaire was used for one sample consisting of three-eighths of the full sample, and the traditional questionnaire was used for the remaining five-eighths of the full sample. In this text, the poverty estimates cited for 1978 are based on the full sample. In addition, the full sample for 1978 was also used to measure changes from 1977. A discussion of the experiment and its impact on 1978 poverty data is provided in a later section entitled, "The March 1979 CPS Income Experiment."

This report presents detailed social and economic statistics for the population of the United States below the poverty level in 1978 based on the March 1979 Current Population Survey (CPS). As in previous poverty reports, data are presented by selected characteristics such as race, family relationship, type of residence, education, work experience, and type and source of income. For the first time, data on the poverty status of families and unrelated individuals before receipt of selected cash transfer payments have been included (table 41). It should be noted that the term "householder" has been used in the text of this report in place of the term "head," which still appears in the detailed tables. See the section, "Head vs. Householder" for further details.

The poverty threshold for a nonfarm family of four persons was $6,662 in 1978, about 7.6 percent higher than the comparable 1977 figure of $6,191. The poverty thresholds are updated every year to reflect changes in the annual average Consumer Price Index (CPI). (See page 205 for a detailed explanation of the poverty concept.) In this text, the terms "poverty," "low-income," and "poor" are used interchangeably. Also, the terms "families with male householder" and "families with female householder, no husband present" are synonymous with the terms "families maintained by men" and "families maintained by women."