In 1960, a married couple is defined as a husband and wife enumerated as members of the same household. Data are not available for the very small number of married couples living as inmates of institutions or as other members of group quarters. A married couple with own household is a married couple in which the husband is a household head.
An own child of a married couple is defined as a single (never married) son, daughter, stepchild, or adopted child of the couple. Persons under 18 living with both parents include stepchildren and adopted children as well as sons and daughters born to the couple.

A family consists of two or more persons in the same household who are related to each other by blood, marriage, or adoption; all persons living in one household who are related to each other are regarded as one family. In a primary family, the head of the family is the head of a household. Other families are secondary families. An unrelated individual is a member of a household who is not related to anyone else in the household, or is a person living in group quarters who is not an inmate of an institution. A head of a household living alone or with nonrelatives only is a primary individual.

The three major race categories distinguished in this report are white, Negro, and other races. Among persons of other races are American Indians, Japanese, Chinese, Filipinos, Koreans, Asian Indians, and Malayans. Negroes and persons of other races taken together constitute nonwhite persons. Persons of Mexican birth or descent who are not definitely Indian or other nonwhite race are classified as white. In addition to persons of Negro and of mixed Negro and white descent, the category Negro includes persons of mixed Indian and Negro descent unless the Indian ancestry very definitely predominates or unless the person is regarded as an Indian in the community.

Information on income for the calendar year 1959 was requested from all persons 14 years old and over in the sample. Total income is the sum of amounts reported separately for wage or salary income, self-employment income, and other income. Wage or salary income is defined as the total money earnings received for work performed as an employee. It represents the amount received before deductions for personal income taxes, Social Security, bond purchases, union dues, etc. Self-employment income is defined as net money income (gross receipts minus operating expenses) from a business, farm, or professional enterprise in which the person was engaged on his own account. Other income includes money income received from such sources as net rents, interest, dividends, Social Security benefits, pensions, veterans payments, unemployment insurance, and public assistance or other governmental payments, and periodic receipts from insurance policies or annuities. Not included as income are money received from the sale of property (unless the recipient was engaged in the business of selling such property), the value of income in kind, withdrawals of bank deposits, money borrowed, tax refunds, and gifts and- lump-sum inheritances or insurance payments. Although the time period covered by the income statistics is the calendar year 1959, the composition of families refers to the time of enumeration. For most of the families, however, the income reported was received by persons who were members of the family throughout 1959.