in time. The need to monitor or gauge important social changes and movements cannot adequately be met by means of observed net differences over time.

Gross flows and transactions can only be estimated via some kinds of longitudinal surveys whereby the same units of observation can be traced through time. (See the chapter on longitudinal surveys.) In short, the mid-decade effort must be regarded as a means for testing the initial framework and providing it with a set of base line observations. The true research value of that framework can only be realized if subsequent data collection efforts are made congruent with the same basic framework.19

The guiding principles for such an effort include recognizing that, first, the basic task is one of information processing rather than data collection; second, that the major purpose of information processing is to provide objective, accurate, timely and relevant information to policymakers; third, that relevance to the needs of policymakers implies the development of a variety of representational entities (that is, concepts and classifications) which reflect complex social realities; fourth, that the goal is to deepen our understanding of social processes rather

than merely to describe more fully our current condition; and finally, that the data collected must be analyzed and presented within a normative framework so as to inform us as to our progress toward our social goals and objectives.20

19Censuses and large-scale social surveys are not the only vehicles which can provide useful base line estimates for subsequent analysis of social change. Many smaller-scale studies also merit replication. On this point, see Otis Dudley Duncan, Toward Social Reporting: Next Steps (New York: Russell Sage Foundation, 1969). For insight into the technical problems encountered in trying to estimate gross flows over time, see Abbott L. Ferriss, A Test of Demographic Accounting Methods with U.S. Data on Education (Atlanta, Ga.: Emory University, Interim Report, September 15, 1976.)

20If the involvement of social indicators and social accounting with political issues is inescapable, their involvement with questions of social philosophy is equally inevitable. For insights with repect to these problem areas, see Peter J. Henriot, Political Aspects of Social Indicators: Implications for Research (New York: Russell Sage Foundation, 1972); Isabel V. Sawhill, "Social Indicators, Social Accounting and the Future of Society," in Albert Somit (ed.), op. cit., pp. 114-127; Wolfgang Zapf, "Systems of Social Indicators: Current Approaches and Problems," International Social Science Journal, XXVII: 3 (1975), pp. 479497; and Mancur Olson, Jr., "Social Indicators and Social Accounts," Socioeconomic Planning Sciences, Vol. 2 (1969), pp.335346.

Introduction

Virtually all agencies in the Federal Government which engage in extensive statistical work use electronic computers. The availability of electronic data processing equipment and the increasing demand for statistics for research and policy formation have resulted in a growing volume of published statistics from these agencies, as well as a new storage medium, the machine-readable data file. Identification and easy access to computerized data files is essential for purposes of research, policy formulation, and publication. Consequently, the importance of guides to aid access to computerized data files has increased.

Any consideration of public access to Federal computerized data files must be based on an assessment of user needs. Recent limited surveys of current and potential nonfederal users of Federal machinereadable data suggest the following general facts and problems concerning access:

1. The number of nonfederal researchers and policymakers with ADP capabilities is steadily increasing. These data users can be divided into two broad groups. There is a definite user elite consisting of those with sufficient experience or other resources to acquire data, from whatever source, with relative speed and ease. The second group of general data users must struggle mightily or rely on luck to locate desired data. Even the members of the "user elite," who are served adequately, if not well, by Federal agencies perceive needs for improvement in data access. They encounter difficulties when pursuing data outside their customary areas of contact and when desiring special data prod

ucts.

2. A copy of a file on magnetic tape is most often sought by users, as well as special extracts and tabulations. With the exception of time series data, there seems to be only a limited desire for on-line access to Federal data.

3. Users have developed a generally effective system of communications among themselves,

both informally and through the rather recent growth of data user organizations. The information exchanged largely concerns data needs, sharing of access cost, and problems with data use.

4. Users seldom purchase data solely on the basis of published descriptions in agency directories. Although such advertising is an indispensable part of a system for data access, users prefer and need to contact agency personnel for detailed information on data elements, formats, etc. Such needs make it vastly preferable that agencies have a centralized data users service organization.

5. Technical problems with data, although decreasing, are still common among nonfederal users. The majority of these problems can be traced to inadequate technical documentation, communications, or procedures within the

agency.

6. Charges for data present problems for users in two major respects. There is a great disparity in rates among Federal agencies. Also, procedures for billing and payment vary from agency to agency, causing difficulty for both data users and providers.

7. Users' unmet needs for data focus on finer geographic distinction and more detailed and frequent data on income, housing, and employment.

8. Users identify the following as major current problems regarding access to Federal data:

a. Locating data (users overwhelmingly favor the development of centralized contact to focus data access for all Federal files); b. Cost of data;

c. Currency of data;

d. Communication with agencies; and e. Quality of data.

A review of the ways in which several Federal agencies facilitate data access reveals a great variance

in policies and procedures, which impact on users. The following summarizes what some of the agencies have done to facilitate access to their data, whether available in published form or on computer tape. The data which are available in machine-readable form include data which are not published because the volume is too great.

Description of Selected Agency Activities

Bureau of Labor Statistics

The Bureau of Labor Statistics (BLS) in the Department of Labor is the principal data gathering agency of the Federal Government in the field of labor statistics. BLS collects, organizes, and disseminates data relating to employment and unemployment, productivity, prices, family expenditures, wages, industrial relations, and occupational safety. BLS has issued several publications which are aids in accessing information available in published form. These include the following:

-Major BLS Programs provides a listing of BLS activities. Each program is outlined and information is provided which describes the purpose and scope of each activity, collection methods, data development, analytical use, and publications which report on findings.

-Publications of the Bureau of Labor Statistics is a semiannual catalog having an annotated listing of bulletins, reports, releases, and Monthly Labor Review articles and reprints; and

-Publications of the Bureau of Labor Statistics, 1886-1971 contains a listing of all numbered bulletins and reports issued by BLS since 1886. It contains selected annotations and a subject index.

These reference materials are excellent guides to accessing BLS data available in published form.

BLS time series and survey data are available in machine-readable form. BLS has established a system which contains summary data generated from its statistical surveys. The BLS data system is divided into a number of separate data files, each containing BLS statistics on a particular subject, for example, the Consumer Price Index, labor force, and Wholesale Price Index. By the end of the year BLS expects to have a data system with 150,000 time series that will be accessible on an interactive basis from remote sites. At present, plans are to make these data available within BLS and select federal agencies. This fall BLS plans to reissue an updated public catalog of its data holdings. Tape reel copies of the data will be

available for a small fee. A description of data and analytical routines contained in its system and other machine-readable data files can be found in BLS Data Bank Files and Statistical Routines (Report 507, 1978). This booklet contains data file descriptions which summarize published data stored in each file. Brief notes on the nature and scope of the statistical programs which yield these data are also provided as a guide to prospective users. BLS publications in which the data appear also are indicated. This booklet also includes documentation pertaining to BLS computer equipment and file format so as to help potential users evaluate the Bureau's data holdings in light of their research requirements and the processing capabilities available to them.

BLS is an agency registered with the National Technical Information Service, and tapes available through NTIS are listed in the NTIS Directory of Computerized Data Files, and Related Reports. Tapes are available on such subjects as labor force, employment and earnings, area wage surveys, and Survey of Consumer Expenditures.

Bureau of the Census

The Bureau of the Census in the Department of Commerce is the largest agency of the Federal Government involved in the collection, compilation, and publication of general-purpose statistics. In addition to its responsibility for taking all censuses authorized by law, the Census Bureau also collects and publishes statistics on construction activity and personal income. The Census Bureau also conducts sample surveys on a weekly, monthly, quarterly, and annual basis. These surveys encompass some of the same subjects as the major censuses, and provide more current information on social and economic conditions.

The Bureau of the Census publishes only the most essential and most widely useful data in its printed reports of censuses and surveys. As an aid to accessing Census data, the Bureau has published a wide variety of guides, reference works, and explanatory material, some of which are described below.

-Index to 1970 Census Summary Tapes (March 1973) contains a cross-reference guide to all tabulations in all six counts of the 1970 census summary data, organized alphabetically by subject. This index helps identify and locate specific tables (on the tape) for specific subjects.

-Index to Selected 1970 Census Reports (1974) is an index to the tables found in selected series of reports: Population Volume I; Housing Volumes I, II, and III; and Census of Population and Housing Vo

lumes I and II. It does not include subject reports and only final reports are indexed.

-Bureau of the Census Guide to Programs and Publications: Subjects and Areas, 1973 (March 1974) provides a review of the Bureau's programs and published reports for each subject area. Reports, presented in tabular format, are listed by title, geographic areas, and principal subjects.

-Bureau of the Census Catalog, an annual publication with monthly supplements, contains a listing of reports on all subjects, an index to their contents, and a description of available data files, special tabulations, and other unpublished materials. An historical volume, Bureau of the Census Catalog of Publications, 1970-1972, presents a compilation of all material issued during that period.

-Mini-Guide to the 1972 Economic Censuses (November 1973) is a valuable reference to each of the nine economic census programs, to the data collected, and publications programs.

-Guide to the 1972 Census of Governments (February 1975) gives a summary description of each subject volume from the 1972 Census of Governments.

-Guide to Recurrent and Special Governmental Statistics (May 1972) summarizes the tabular and graphic presentations found in the recurrent reports and special studies series of the governmental statistics programs. It also includes a listing of all special studies since 1936, and examples of tables.

-Census Bureau Guide to Transportation Statistics (March 1976) describes the 1972 Census of Transportation. It contains descriptions or lists of the data contained in the published reports, indicates availability of unpublished data and of survey results, and describes record content of the public use tapes. -Guide to Foreign Trade Statistics: 1975 (July 1975) describes content and format of individual reports, tabulations, computer tapes, punch cards, and microfilm on exports, imports, and shipping statistics.

-1970 Census Users' Guide, Parts I and II (October 1970) is a guide to the 1970 Census of Population and Housing, containing information on the background, collection, processing, and output (data products) of the 1970 census.

-Directory of Federal Statistics for Local Areas: A Guide to Sources, 1976 (March 1978) updates the 1966 publication. It provides table-by-table descriptions of printed statistical reports on areas smaller than States.

-Census Bureau Methodological Research is an annual annotated list of staff papers and publications on methodological research.

Further information on means of access to Census Bureau data is provided by the series entitled Data Access Descriptions. These are topical, user-oriented reports on accessing and using census data and products. Each issue deals with a specific topic such as census geography, 1970 census summary tapes, Spanish ancestry population, and selected racial groups. Availability of Census data in published form or on computer tape is indicated for each subject.

In addition to published reports, the Census Bureau has extensive tabulations of data available on computer tape. The majority of these files are products of the Bureau's regular data processing and tabulation programs. Other files and special tabulations are prepared at users' requests. Availability of Census data on computer tape is described in detail in Data Access Descriptions, Data Users News (a monthly newsletter), and Part II of the Bureau of Census Catalog.

The Customer Services Branch of the Data User Services Division has also compiled a xeroxed listing entitled "Computer Tape/Files Available from the Bureau of the Census." This is a list of currently available tape files arranged under four categories data files, special tabulations, geographic reference files, and computer program tapes. A short narrative highlights the contents of each file.

The Census Bureau also has registered some of its public-use tapes with NTIS. A listing of these can be found in the NTIS Directory.

From the foregoing discussion, it can be seen that the Bureau of the Census has ample reference material to aid in accessing its data. However, to facilitate access to its computerized data files Census should investigate the possibility of compiling one guide to Census data available on tape.

National Technical Information Service

The National Technical Information Service (NTIS) of the Department of Commerce is a central source for federally generated machine processable data files. Many Federal agencies have registered their reports with NTIS. NTIS has compiled a Directory of Computerized Data Files, Software, and Related Technical Reports as a guide to machinereadable data files, data bases, software and reports available from these agencies. This Directory is a bibliographic reference which lists and describes more than 500 items. NTIS data files are available only in summary form and do not identify individuals

or reporting units. A detailed description of NTIS products and services can be found in a booklet entitled NTIS Information Services.

Social Security Administration

The Office of Research and Statistics, the chief research source for SSA, collects extensive economic, demographic, and other data in the course of administering the Old-Age Survivors, Disability Insurance programs on the old-age, survivors, and disability, and other income security programs. It also collects data and undertakes studies that contribute to program evaluation and policy formation. Much of the data are summarized in the monthly Social Security Bulletin, its Annual Statistical Supplement, Monthly Benefit Statistics, and in special releases and reports.

ORS issues two publications as guides to the availability of its publications and data files.

Research Publications, updated regularly, identifies and briefly annotates recent Bulletin articles and research publications produced by the Office of Research and Statistics. Research publications appear in one of the following series: Research and Statistics Notes, ORS Research Reports, ORS Staff Papers, Disability Survey Reports, Studies in Income Distribution, and Studies from Interagency Data Linkages.' These publications are cataloged under the following general headings: (1) program data and history, (2) retirement and survivors research, (3) disability research, (4) supplementary security income research, (5) economic and long-range research, and (6) foreign social security studies.

Some Statistical Research Resources Available at the Social Security Administration describes the public use files available, how they are compiled, and how they may be obtained. In particular, the publication describes the general-purpose research files making up the Continuous Work History Sample (CWHS). The employee-employer sample files contain such data as quarterly wages, age, race, sex, geographic location, and industrial activity for approximately 1.4 million covered workers.

SSA has also made available several other nonconfidential public-use files through distributing services like the NTIS and the National Archives Record Service. These include such tapes as the March 1973 Current Population Survey (CPS) data files developed by SSA's Office of Research and Statistics, which served as the basis for a comparative study of income reporting in the Current Population Survey. Produced as part of a joint interagency effort to improve available data on income distribution and

redistribution, these files contain income information. from the Census Bureau's Population Surveys matched to SSA earnings and benefit data and selected Federal income tax return items for individuals for calendar years 1963 and 1972.

National Center for Health Statistics

The National Center for Health Statistics (NCHS) in the Health Resources Administration, Department of Health, Education, and Welfare, is the primary source of statistical data on vital events, health, and related matters pertaining to the American people. Data are obtained from a number of statistical data collection systems: The national vital registration system, covering births, deaths, fetal deaths, marriages, and divorces; surveys based on samples of birth and death records; a continuing nationwide health survey of households by means of interviews; a series of national surveys based on physical examinations of samples of the population; periodic surveys of institutions and records on their patients or residents; a continuous national sampling of shortstay hospital records; and surveys of various categories of health manpower based on license renewals, reports from establishments, and other sources.

The published report is the primary method used to distribute data collected by NCHS. These reports are in several series including the annual volumes Vital Statistics of the United States, the Monthly Vital Statistics Report, and the Vital and Health Statistics series.

In addition to publishing reports, NCHS also makes data available on computer tapes. NCHS has recently published a new edition of Standardized Micro-Data Tape Transcripts, a catalog of the data tapes currently available. This catalog describes the approximately 80 data sets, lists the contents of each, and provides information on format and documentation. Data now available on tape include statistics on health manpower and facilities, health resources utilization, and vital events, and data from the National Natality and Mortality Followback Surveys, the Health Interview Survey, and the Health Examination Survey.

NCHS plans to make additional data from their survey available for release to the public on tape to facilitate user access.

National Center for Education Statistics

The National Center for Education Statistics (NCES) in the Education Division, Department of Health, Education, and Welfare, is responsible for statistics relating to the educational system of the