Private Lives and Public Policies Confidentiality and Accessibility of Government Statistics (1993) / Chapter Skim
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6 Technical and Administrative Procedures
6 Technical and Administrative Procedures
Pages 141-180
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From page 141... ...
A computer malfunction in Chicago caused more than 650 veterans to receive another veteran's income tax information. Washington Post, May 27, 1992 INTRODUCTION The general and agency-specific information statutes discussed in Chapter 5 provide the framework for the confidentiality and data access policies and practices of federal statistical agencies.
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From page 142... ...
Insteac] of restricted data and restricted access, they used the terms safe data and safe setting.)
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From page 143... ...
In so cloing, we address four topics: the nature of disclosure risk and statistical procedures for disclosure limitation; current statistical disclosure limitation practices of federal statistical agencies; the impact of increased computer and communications capability on disclosure risk; and current statistical disclosure limitation research. DISCLOSURE RISK AND STATISTICAL DISCEOSURE LIMITATION TECHNIQUES As defined in Chapter 1, a disclosure occurs when a data subject is identified from a released file {identity ciisc~osure)
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From page 144... ...
On the other hand, the concept of inferential disclosure is useful to statistical agencies developing and analyzing statistical disclosure limitation techniques. Also, inferential disclosure encompasses a broader range of confidentiality risks that an agency should examine.
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From page 145... ...
of data subjects that are not needed for statistical purposes. In many situations, however, this obvious step of Reidentification or anonymization is not adequate to make the risk of disclosure reasonably iow.4 To go beyond ad hoc measures to reduce the risk of disclosure, it is necessary to have ways of measuring the nature and extent of disclosure possible in specified circumstances.
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From page 146... ...
In the case of a public-use microdata file, statistical disclosure limitation techniques can be classified into five broad categories Duncan and Pearson, 1991J: 1. Co1Jecting or reJeasir~g only a sample of the data: For example, the Bureau of the Census first released a public-use microdata file with a 1-in-1,000 sample from the 1960 Census of Population and Housing; microdata products from the 1980 census included one based on a 1 percent sample and another based on a 5 percent sample.
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From page 147... ...
SELECTED STATISTICAL DISCLOSURE LIMITATION PRACTICES OF FEDERAL STATISTICAL AGENCIES Some federal statistical agencies notably the Census Bureauhave devoted considerable attention to the development and implementation of statistical disclosure limitation techniques.8 In an enduring contribution, the Federal Committee on Statistical Methodology {1978) issued Statistical Policy Working Paper 2, Report on Statistical Disclosure and Disc~osure-Avoidance Techniques.
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From page 148... ...
Procedures for Microdata Files Only about half of the federal statistical agencies that replied to the panel's request for information included materials that documented their statistical disclosure limitation techniques for microdata. Some that did merely indicated that the statistical disclosure limitation techniques for surveys they sponsored were set by the Census Bureau's Microdata Review Panel because the surveys tract been conducted for them by the Census Bureau.
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From page 149... ...
The Census Bureau and NCHS specify that no geographic codes for areas with a population of less than 100,000 can be included in public-use microciata files. If a file contains a large number of variables, a higher cutoff may be used.
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An often-cited example of such an arrangement is the Luxembourg Income Study (Rainwater and Smeeding, 1988) , which maintains microclata sets containing measures of economic well-being for many developed countries.
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Below we describe a few recent studies of statistical disclosure limitation techniques.
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, in his paper Statistical Disclosure Limitation: Current Federal Practices and Research, summarizes the statistical disclosure limitation practices of 18 agencies based primarily on their responses to a 1990 request from the pane! for information about agency confidentiality and data access policies and practices.
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Shielding Organizational Data For the most part, statistical disclosure limitation techniques have been developed for data on persons and households. The task of protecting the confidentiality of organizational data for example, economic data on establishments is more difficult be
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From page 154... ...
appropriate statistical disclosure limitation techniques are applied prior to release of tables and public-use microdata files. The stanclarcis and guidelines, however, exhibit a wicle range of specificity: Some contain only one or two simple rules; others are much more detailed.
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From page 155... ...
Recommendation 6.1 The Office of Management and Buciget's Statistical Policy Office should continue to coordinate research work on statistical disclosure analysis and should disseminate the results of this work broadly among statistical agencies. Major statistical agencies should actively encourage and participate in scholarly statistical research in this area.
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From page 156... ...
Agencies should avoid framing regulations and policies which define unacceptable statistical disclosure in unnecessarily broad or absolute terms. Agencies should apply a test of reasonableness, i.e., releases should be made in such a way that it is reasonably certain that no information about a specific individual will be disclosed in a manner that can harm that individual {p.
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From page 157... ...
Recommendation 6.3 Each statistical agency should actively involve data users from outside the agency as statistical disclosure limitation techniques are developed and applied to data. Finally, over the past 30 years various agencies have released public-use microdata files successfully.
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From page 158... ...
Arrangements for providing restricted access to federal data for statistical purposes are not uncommon. In a paper prepared for the panel, Jabine t1993aJ provides 19 examples, most of them current, and his list was intended only to illustrate various types of access that are allowed, not to provide an exhaustive summary.
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From page 159... ...
The agreement and attached statement of policies provide for strict security measures by BLS staff, periodic on-site inspections by the Census Bureau, and regular reviews of the benefits of the sharing arrangement. Linkage of Records from the Departments of Defense and Health and Human Services This example also covers restricted access to data for statistical purposes.
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From page 160... ...
100-503) because that act does not cover matches performed solely for statistical purposes.
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, limited extracts of CPS records were used and those records were processed only by SSA employees who had been given appointments as special sworn employees of the Census Bureau. The primary personal identifier user!
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From page 162... ...
Over the years, the Census Bureau has used those records in several ways to enhance its demographic censuses and surveys and to evaluate the quality of census and survey data. Census Bureau uses of IRS and SSA administrative data can perhaps be best illustrated by explaining how the data serve as basic inputs to the Census Bureau's program of intercensal population estimates for small areas.
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From page 163... ...
As explained in Chapter 5, the Internal Revenue Code allows certain statistical uses of tax return information by the Census Bureau. Specific uses are spelled out in some detail in a series of Treasury Department regulations that identify the content of the records to be transferred, the uses to which they can be put, and the security measures that must be adopted to protect the confidentiality of information turned over to the Census Bureau.
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From page 164... ...
In general, data sharing among federal agencies other than the Census Bureau and IRS for statistical purposes is less constrained by legislation. However, statistical agencies that receive some of their data from the states under federal-state cooperative programs (e.g., BLS and NCHS)
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From page 165... ...
has administered a program designed to promote the exchange of ideas and techniques between federal government statisticians and academic users of federal statistical data. Five agencies, the Bureau of Labor Statistics, the Census Bureau, the National Center for Education Statistics, the National Institute of Standards and Technology, and most recently, the National Science Foundation (as a host agency)
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From page 166... ...
They have essentially the same access to agency data bases and computer facilities as regular employees doing similar work, and they are subject to the same confidentiaTity requirements and penalties for improper disclosure of individually identifiable information. At the Census Bureau, for example, the ASA/NSF/Census fellows receive appointments, take oaths as special sworn employees, and are subject to the same Title 13 confidentiality provisions, including penalties for violations, as regular employees.
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From page 167... ...
To prevent disclosure of individual records, incoming job requests and statistical outputs are subjected to automated reviews ant! those that fait the review are given to the Luxembourg Income Study staff for further review.
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From page 168... ...
Microdata sets containing linked survey and administrative data could then be released with very little risk that the custodians of the administrative records could reidentify individual records. Release of Microdata under Licensing Agreements To meet the requirements of users whose needs cannot be satisfied with public-use or encrypted CD-ROM microdata sets, the NCES has developed a licensing procedure that allows eligible organizations or agencies to use its confidential data for research and statistical purposes at their own sites {see Wright and Ahmed, 19901.
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From page 169... ...
The Statistical Policy Office, OMB, has announced that the licensing procedures and agreement will be submitted to a formal regulatory review, including publication in the Federal Register and comment by all interested groups. Examples of Failure to Gain Access SSA's Continuous Work History Sample The Social Security Administration established its Continuous Work History Sample jCWHSJ system about 50 years ago to serve as a multipurpose longitudinal data base for program analysis ant!
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From page 170... ...
/ As explained in Chapter 5, the Tax Reform Act of 1976 severely curtailed the use of identifiable tax return information for statistical purposes by users outside the IRS. Both the employer information from Employer Identification number applications and the earnings data were considered to be tax return information, and thus, the release of CWHS files containing such data came unpiler the new provisions of the Internal Revenue Code.
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From page 171... ...
Provisions of the 1976 Tax Reform Act permit both of these agencies to use tax return information under certain conditions, so one cannot anticipate similar releases to the many potential users who do not have this authority. One possibility for wider release would be to clevelop one or more versions of the CWHS containing less detailed information for characteristics like industry classification and geographic location of employment.
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From page 172... ...
There was some discussion of extending the coverage of the National Death Index back to about 1965, but that was found to be infeasible. The Social Security Administration releases information about date and place of death to the public from its own files, and epidemiologists can obtain this information about members of study populations they are tracking.
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From page 173... ...
Finally, SSA has little if any information on current addresses for nonbeneficiaries except on tax records that are subject to the Internal Revenue Code's restrictions on disclosure. Discussion These examples illustrate the wide spectrum of modes of external user access to federal statistical data, ranging from no access at all to completely unrestricted access.
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From page 174... ...
Archiving Procedures All federal agencies, including statistical agencies, operate under statutorily prescribed information management procedures that oblige them to notify the NARA of proposed schedules for disposition of their records. In turn, NARA reviews the proposed schedules and, when it consiclers the records to "have sufficient administrative, legal, research, or other value to warrant their further preservation by the United States Government" (Title 44 U.S.C.
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From page 175... ...
provisions of the 1952 agreement to records from the Current Population Survey and other demographic surveys conducted by the Census Bureau. The 72-year period of confidentiality does not apply to any public-use microdata files that are transferred to the National Archives, but it would apply to internal Census Bureau survey data files whose content had not been restricted to make them suitable for unrestricted public access.
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From page 176... ...
The National Archives is actively pursuing transfers from these data bases. RESTRICTED ACCESS: FINDINGS AND RECOMMENDATIONS Recommendation 6.5 Federal statistical agencies should strive for a greater return on public investment in statistical programs through carefully controlled increases in interagency data sharing for statistical purposes and expanded availability of federal data sets to external users.
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From page 177... ...
Recommendation 6.6 Statistical agencies, in their efforts to expand access for external data users, should follow a policy of responsible innovation. Whenever feasible, they should experiment with some of the newer restricted access techniques, with appropriate confidentiality safeguards and periodic reviews of the costs and benefits of each procedure.
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From page 178... ...
NOTES 1. Statistical disclosure limitation techniques are often referred to as disclosure control or disclosure avoidance.
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From page 179... ...
Early discussions include Bachi and Baron {19691 and Steinberg and Pritzker (1967J. Bailar {19901 identifies the development of statistical disclosure limitation techniques to be one of the five major contributions of the Census Bureau.
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