Statistics on Years of School Completed by the population 25 years old and over, based on a 25-percent sample tabulation, for the United States, regions, divisions, States, standard metropolitan statistical areas, Urbanized Areas, urban places, and counties have been published in chapter C of the 57 parts of 1960 Census of Population, Volume I, Characteristics of the Population. More detailed data on Years of School Completed by age from the same sample, for persons 14 years old and over, for the United States, regions, divisions, States, and standard metropolitan statistical areas and counties of 250,000 or more have been published in chapter D of 1960 Census of Population, Volume I, Characteristics of the Population. Part 1 of Volume I includes these two chapters for the United States as a whole; the remaining parts of Volume I are for each State and for outlying areas. The chapters C and D were originally published as paper-bound Series PC(1)-C reports, "General Social and Economic Characteristics," and Series PC(1)-D reports, "Detailed Characteristics."

Statistics on educational attainment of the population 25 years old and over are also shown in the reports for census tracts of large cities and adjacent areas. These data are presented, for 180 areas, in 1960 Censuses of Population and Housing, Census Tracts, Series PHC(1).

Additional statistics on educational attainment are included in virtually all other 1960 Census of Population Subject Reports, Series PC(2), which either have already been published or are being planned for publication.

Additional statistics on educational attainment are also presented in the 1960 Census of Population Selected Area Reports, Series PC(3), on State economic areas; size of place; standard metropolitan statistical areas; and Americans overseas.

Data on Years of School Completed, based on a 20-percent sample of the population, for regions, divisions, States, standard metropolitan areas, Urbanized Areas, cities, and counties were published in 1950 Census of Population, Volume II, Characteristics of the Population, and for census tracts in Volume III, Census Tract Statistics. Data on educational attainment from a 3 1/3-percent sample, cross-classified by many of the characteristics shown in this report, were published in a report entitled "Education," which was Part 5B of Volume IV, Special Reports, of the 1950 Census of Population reports; additional data on educational attainment, cross-classified by various subjects, were part of other special reports in Volume IV.

Data on educational attainment for the United States as a whole are collected regularly and published periodically by the Bureau of the Census through its Current Population Sur-vey (CPS). The CPS is a nationwide survey, covering a sample of about 35,000 interviewed households. These data are published in Current Population Reports, Series P-20. Statistics on educational attainment by income are shown in the Series P-60 reports, and those on the educational attainment of the labor force are published in Special Labor Force Reports issued by the Bureau of Labor Statistics, U.S. Department of Labor. (For a statement on the comparability of CPS and census data on Years of School Completed, see the paragraphs on "Comparability" in the section on "Definitions and explanations" below.)

Data on illiteracy, in terms of inability to read and write in any language, are collected occasionally through the CPS and are published in the Series P-20 reports. Estimates of illiteracy for States as of 1960 are shown in Series P-23, No. 8.

Projections to future years of the educational attainment of the population are prepared at intervals by the Bureau staff and are published in the Series P-20 reports.