Data Sets, Linkages, Quality, and Evaluation
This article provides an overview of the Understanding America Study (UAS), a nationally representative Internet panel of approximately 6,000 adult respondents that is administered by the University of Southern California. The UAS, which began in 2014, represents one of the richest sources of panel data available in the United States. It includes over 50 survey modules on topics such as retirement planning, economic well-being, and psychological constructs. This article reviews the UAS methodology; describes how external researchers may commission UAS surveys, incorporate their own survey questions and methodological experiments, and conduct randomized controlled trials; highlights selected publicly available data from UAS surveys on cognition, personality, financial literacy and behaviors, political views, and other topics; and discusses opportunities for external parties to work with UAS administrators in developing new surveys and future lines of research.
In this article, the authors examine the relationship between prevailing economic conditions and the likelihood of application for Supplemental Security Income (SSI) payments by jobless adults with disabilities. Using data for 1996–2010 from the Survey of Income and Program Participation linked to Social Security administrative records, the authors observe samples of jobless individuals and examine the state-level unemployment rates at both the time their unemployment spell began and at the time they applied for SSI.
Social Security benefits are the most important source of U.S. retirement income. Over time, however, trends in employer-provided pension offerings, societal changes, and Social Security program rule changes have altered the distribution of income by source among the aged population. In this article, the authors examine the reliance on Social Security benefits of people aged 65 or older using data from the Current Population Survey, the Survey of Income and Program Participation, and the Health and Retirement Study.
Why Researchers Now Rely on Surveys for Race Data on OASDI and SSI Programs: A Comparison of Four Major Surveys
Policy interest in the sociodemographic characteristics of beneficiaries of the Old-Age, Survivors, and Disability Insurance (OASDI) and Supplemental Security Insurance (SSI) programs is increasing as the minority share of the senior and disabled population grows. This note discusses using four major surveys—the Current Population Survey, the Survey of Income and Program Participation, the American Community Survey, and the Health and Retirement Study—to examine OASDI and SSI program use by race and ethnicity. Survey profiles highlight each survey's history, design, and methodology; the categories with which each collects race and ethnicity data; and their strengths and limitations for analyzing SSA's program data.
Longitudinal Patterns of Disability Program Participation and Mortality Across Childhood SSI Award Cohorts
This article follows six annual cohorts of childhood Supplemental Security Income (SSI) disability awardees between 1980 and 2000, for a time horizon up to 30 years after initial SSI award, in many cases well into adulthood. The authors compare trajectories of successive awardee cohorts as the SSI program evolves from 1980 to recent years. The results show that the proportion of awardees in SSI-only status declines over the life cycle, with over half transitioning to other statuses roughly after 10 to 15 years. Many awardees transition from the SSI program to concurrent or Disability Insurance–only benefit status, and increasing proportions of awardees are deceased or off the rolls and alive. These patterns are common for all awardee cohorts, but there are major changes in trajectories across cohorts. Compared with the early cohorts, the more recent cohorts display sharper declines in mortality and steeper increases in the proportion off the disability rolls for other reasons. These two trends have opposite effects on the duration of disability program participation over the life cycle, with important policy implications.
Source, Form, and Amount of In-kind Support and Maintenance Received by Supplemental Security Income Applicants and Recipients
This article examines the in-kind support and maintenance (ISM) received by Supplemental Security Income (SSI) program applicants and recipients. Social Security defines ISM as unearned income received by SSI applicants and recipients in the form of food and/or shelter from anyone living within or outside their households. About 9 percent of SSI recipients have their benefit rates reduced because of ISM during any given year. Using data from the Modernized SSI Claims System, the author quantifies the source, form, and amount of ISM received by SSI recipients. The article reveals that SSI recipients are more likely to receive ISM from outside than inside their homes, receive assistance in the form of shelter rather than food, and allege assistance that is equal to or less than the current ISM caps.
The deduction of Medicare premiums from Social Security benefit payments complicates the estimation of Social Security income in household surveys. Although the Census Bureau's Current Population Survey (CPS) and Survey of Income and Program Participation (SIPP) both aim to collect and record gross Social Security benefit income before Medicare premium deductions, comparing the survey data with Social Security records indicates that the CPS and SIPP estimates differ and suggests that some survey respondents may report net benefit income.
The authors document the steps used by the Social Security Administration (SSA) and state Disability Determination Service (DDS) agencies to make initial determinations about eligibility for Disability Insurance and Supplemental Security Income. For both adults and children, SSA/DDSs record the basis for initial disability determinations using codes that correspond to the steps of the process. The resulting data element, the Regulation Basis Code, permits researchers to distinguish allowances based on the Listings from those based on medical/vocational factors for adults (or functional factors for children). It can also be used to identify denials based on severity, residual functional capacity, or other reasons.
The income of the aged is composed largely of Social Security benefits, asset income, and pension income. Over the past three decades, the primary form of employer-sponsored pension has shifted from the traditional defined benefit plan to defined contribution plans, such as the 401(k). That trend creates problems for measuring the income of the aged because most household surveys of income either do not collect information about distributions from defined contribution retirement accounts or do not include those distributions in their summary measures of income. This article examines the impact of including distributions from retirement accounts on the estimated income of families headed by persons aged 65 or older.
Outcome Variation in the Social Security Disability Insurance Program: The Role of Primary Diagnoses
This article investigates the role that primary impairments play in explaining heterogeneity in disability decisions. Using claimant-level data within a hierarchical framework, the author explores variation in outcomes along three dimensions: state of origin, adjudicative stage, and primary diagnosis. The findings indicate that the impairments account for a substantial portion of claimant-level variation in initial allowances. Furthermore, the author finds that the predictions of an initial and a final allowance are highly correlated when applicants are grouped by impairment. In other words, diagnoses that are more likely to result in an initial allowance also tend to be more likely to receive a final allowance.
Workplace injuries and illnesses are an important cause of disability. States have designed their workers' compensation programs to provide cash and medical-care benefits for those injuries and illnesses, but people who become disabled at work may also be eligible for Social Security Disability Insurance (DI) and related Medicare benefits. This article uses matched state workers' compensation and Social Security data to estimate whether workplace injuries and illnesses increase the probability of receiving DI benefits and whether people who become DI beneficiaries receive benefits at younger ages.
Comparing Earnings Estimates from the 2006 Earnings Public-Use File and the Annual Statistical Supplement
The Social Security Administration recently released the 2006 Earnings Public-Use File (EPUF). The EPUF contains earnings information for individuals drawn from a systematic random 1-percent sample of all Social Security numbers issued before January 2007. This note presents the process of evaluating the earnings data in EPUF. It also identifies and explains four key differences between the data in EPUF and the estimates published in the Annual Statistical Supplement to the Social Security Bulletin. The note specifically compares EPUF data with Annual Statistical Supplement estimates of earnings, number of workers with earnings, median earnings by sex and age group, and percentage of workers with earnings below the taxable maximum by sex. After accounting for the expected differences, the remaining discrepancies between EPUF and Annual Statistical Supplement estimates are relatively small.
This article introduces the 2006 Earnings Public-Use File (EPUF), a data file containing earnings records for individuals drawn from a 1-percent sample of all Social Security numbers issued before January 2007. The EPUF contains selected demographic and earnings information for 4.3 million individuals. It provides aggregate earnings data for 1937 to 1950 and annual earnings data for 1951 to 2006.
Data from administrative records of the Social Security Administration allow us to examine patterns of initial entitlement to Old-Age Insurance benefits as well as Disability Insurance benefits. We follow cohorts born in different years over their lifetimes to identify changes in entitlements by age over time. Breaking out single birth cohorts shows close adherence in entitlement ages to rule changes as well as increasing shares of cohorts relying on the Disability Insurance program in middle age.
Longitudinal Statistics on Work Activity and Use of Employment Supports for New Social Security Disability Insurance Beneficiaries
Longitudinal statistics on the employment activities of Social Security Disability Insurance beneficiaries offer a different perspective than the Social Security Administration's published statistics, which are based on annual data, and have important policy implications.
Longitudinal Patterns of Participation in the Social Security Disability Insurance and Supplemental Security Income Programs for People with Disabilities
We analyze longitudinal interactions in benefit eligibility between the Disability Insurance and Supplemental Security Income programs and the lags arising from processing time in receiving the first payment, based on Social Security administrative records. We find that longitudinal interactions enhancing the bundle of cash benefits available for awardees over a 60-month period is much more common than apparent from cross-sectional data and identify distinct patterns of longitudinal interactions between the two programs. SSI plays an especially important role in providing benefit eligibility during the 5-month DI waiting period. Transition to nonbeneficiary status is more prevalent among SSI awardees because of exits attributable to the SSI means test. We also find that there is substantial variation in the lag in receiving the first disability payment.
Of particular interest in this article is the relationship between firm size and pension coverage and participation because small businesses tend to be less likely to offer retirement benefits to their employees than do large businesses. This relationship is particularly important given the current administration's retirement proposals to create automatic individual retirement accounts. Obviously, accurate information is important not only in formulating retirement income security policies that target workers without retirement plan coverage, but also to assess the impact of such policies on workers' retirement plan participation.
Defined Contribution Pension Participation and Contributions by Earnings Levels Using Administrative Data
This article examines the relationship between earnings levels and participation and contribution rates in defined contribution (DC) retirement plans. Specifically, the article estimates DC plan participation and contribution rates in 2006 both by the worker's current earnings and by the annual average of real earnings over the 10-year period 1997–2006. Using these two different measures of earnings allows us to assess whether employing a longer period of earnings, such as a decade, provides a better representation of pension outcomes than the short-term measure of current earnings.
Expanding Access to Health Care for Social Security Disability Insurance Beneficiaries: Early Findings from the Accelerated Benefits Demonstration
The Accelerated Benefits (AB) demonstration project provides health benefits to Social Security Disability Insurance beneficiaries who have no health insurance during the 24-month period most beneficiaries are required to wait before Medicare benefits begin. This article describes the project and presents baseline survey results on health insurance coverage among newly entitled beneficiaries and the characteristics of those without coverage. A 6-month follow-up survey provides information on the effects of the AB health benefits package on health care utilization and on reducing unmet medical needs. The article also reports the costs of providing the health benefits package during the 24-month Medicare waiting period.
Using Matched Survey and Administrative Data to Estimate Eligibility for the Medicare Part D Low-Income Subsidy Program
This article uses matched survey and administrative data to estimate, as of 2006, the size of the population eligible for the Low-Income Subsidy (LIS), which was designed to provide "extra help" with premiums, deductibles, and copayments for Medicare Part D beneficiaries with low income and limited assets. The authors employ individual-level data from the Survey of Income and Program Participation and the Health and Retirement Study to cover the potentially LIS-eligible noninstitutionalized and institutionalized populations of all ages. The survey data are matched to Social Security administrative data to improve on potentially error-ridden survey measures of income components and program participation.
Selected Characteristics and Self-Perceived Performance of Individual Social Security and Supplemental Security Income Representative Payees
Social Security beneficiaries and Supplemental Security Income recipients who are unable to manage their own benefits may be assisted by relatives, friends, or other interested individuals, called representative payees. This note examines the characteristics of these payees, the payees' assessment of their own performance, and whether they believe their beneficiaries' needs are met. Using results of a survey of representative payees conducted by Westat, Inc. for a 2007 National Research Council report, this note also examines the importance of indicators of potential misuse identified in that report.
The Office of Retirement and Disability Policy at the Social Security Administration created the Retirement Research Consortium in 1998 to encourage research on topics related to Social Security and the well-being of older Americans, and to foster communication between the academic and policy communities. The Michigan Retirement Research Center (MRRC) has participated in the Consortium since its inception. This article surveys a selection of the MRRC's output over its first 10 years and highlights several themes in the Center's ongoing research.
An Empirical Study of the Effects of Social Security Reforms on Benefit Claiming Behavior and Receipt Using Public-Use Administrative Microdata
In the past few years, the Social Security Old-Age and Survivors Insurance benefit system in the United States has undergone some of the most significant changes since its inception. Using the public-use microdata extract from the Master Beneficiary Record, we are able to uncover a number of interesting trends in benefit claiming behavior and level of benefit receipt, which can help us understand how the changes in the system are shaping the retirement benefit claiming behavior of older Americans.
The Social Security Administration (SSA) receives reports of earnings for the U.S. working population each year from employers and the Internal Revenue Service. The earnings information received is stored at SSA as the Master Earnings File (MEF) and is used to administer Social Security programs and to conduct research on the populations served by those programs. This article documents the history, content, limitations, complexities, and uses of the MEF (and data files derived from the MEF). It is intended for researchers who use earnings data to study work patterns and their implications, and for those interested in understanding the data used to administer the current-law programs.
Organizations involved in statistical surveys of human subjects face two important and competing challenges: protecting data confidentiality while maximizing data accessibility to potential researchers. This note examines how the Health and Retirement Study (HRS), conducted by the Institute for Social Research of the University of Michigan, attempts to balance data confidentiality with the desire to broaden the pool of potential data users. Current HRS procedures are summarized and compared with those of organizations with similar programs, and potential ways to expand HRS use without compromising confidentiality are discussed.
Provided here are the absolute and relative poverty status of 2002 elderly Supplemental Security Income (SSI) recipients. Official poverty estimates are generated from the Current Population Survey's Annual Social and Economic Supplement (CPS/ASEC). The poverty study presented here differs from previous studies in that it is based on CPS/ASEC income and weight records conditionally adjusted by matching Social Security administrative data. This effort improves the coverage of SSI receipt and the accuracy of SSI estimates. The adjusted CPS/administrative matched data reveal lower 2002 poverty rates among elderly persons (with and without SSI payments) than those generated from the unadjusted CPS/ASEC data.
This article discusses the advantages and limitations of using administrative data for research, examines how linking administrative data to survey results can be used to evaluate and improve survey design, and discusses research studies and SSA statistical products and services that are based on administrative data.
Benefit Adequacy Among Elderly Social Security Retired-Worker Beneficiaries and the SSI Federal Benefit Rate
The federal benefit rate (FBR) of the Supplemental Security Income program provides an inflation-indexed income guarantee for aged and disabled people with low assets. Some consider the FBR as an attractive measure of Social Security benefit adequacy. Others propose the FBR as an administratively simple, well-targeted minimum Social Security benefit. However, these claims have not been empirically tested. Using microdata from the Survey of Income and Program Participation, this article finds that the FBR is an imprecise measure of benefit adequacy; it incorrectly identifies as economically vulnerable many who are not poor, and disregards some who are poor. The reason for this is that the FBR-level benefit threshold of adequacy considers the Social Security benefit in isolation and ignores the family consumption unit. The FBR would provide an administratively simple but poorly targeted foundation for a minimum Social Security benefit. The empirical estimates quantify the substantial tradeoffs between administrative simplicity and target effectiveness.
Estimates of Unreported Asset Income in the Survey of Consumer Finances and the Relative Importance of Social Security Benefits to the Elderly
Through the 1990s and the early 2000s, the Income of the Population 55 or Older has reported a decline in the proportion of the elderly receiving asset income and the corresponding rise in the proportion receiving all of their income from Social Security. This analysis uses the Survey of Consumer Finances from 1992 to 2001 to examine financial asset holdings of the elderly and to determine if those who do not report asset income in fact might hold assets that are likely to generate income. Imputing asset income from likely income-producing holdings, the article examines the impact of probable missing asset income information upon measures of elderly income.
Provided is a discussion of the cumulative effects of the measurement alternatives described in the three previous articles: considering family income of persons rather than aged units, using administrative data in place of survey reported data, and switching the data source from CPS to SIPP. The current-methodology CPS statistic of 17.9 percent of beneficiary aged units receiving all of their income from Social Security in 1996 falls to a substantially smaller estimated 4.5 percent of elderly beneficiary persons based on family income when using the SIPP and Social Security administrative data.
The Impact of Survey Choice on Measuring the Relative Importance of Social Security Benefits to the Elderly
This article provides insight into how measures of elderly economic well-being are sensitive to the survey data source. In Social Security Administration's publication Income of the Population 55 or Older, data are based on the national Current Population Survey (CPS). The preciseness of the survey statistics depends upon the willingness and ability of CPS respondents to answer questions accurately. This article contrasts income statistics calculated using the CPS and the Survey of Income and Program Participation (SIPP). Administrative data for Social Security benefits and SSI are also used to evaluate the accuracy of the income estimates.
This article summarizes several different methods used to measure the adequacy of wage replacement in state workers' compensation systems in the United States. Empirical research casts serious doubt on benefit adequacy, especially in the case of more serious disabilities.
[Errata: The electronic versions of this article that were originally posted contained incorrect labels on the lines in Chart 3. The labels have been updated in the electronic versions and are correct in the print publication.]
Poverty-level Annuitization Requirements in Social Security Proposals Incorporating Personal Retirement Accounts
In the current discussions of Social Security reform, voluntary personal retirement accounts have been proposed. Recent research and debate have focused on several aspects of these accounts, including how such accounts would affect aggregate saving, system finances, and benefit levels. Little attention, however, has been paid to policies that would govern the distribution of account balances. This analysis considers such policies with respect to the annuitization of account balances at retirement using the Social Security Administration's Modeling Income in the New Term (MINT) model and a modified version of a recent legislative proposal to evaluate the effects of partial annuitization requirements.
Social Security Benefit Reporting in the Survey of Income and Program Participation and in Social Security Administrative Records
The quality of Social Security benefit reporting in household surveys is important for policy research on the Social Security program and, more generally, for research on the economic well-being of the aged and disabled populations. This is particularly true for the aged among whom receipt of Social Security benefits is nearly universal and reliance on such benefits is considerable. This paper examines the consistency between Social Security benefit amounts for May 1990 as reported in the Survey of Income and Program Participation and given in the Social Security Administration's administrative records for the respondent.
The Social Security Administration's Death Master File: The Completeness of Death Reporting at Older Ages
To provide a more detailed assessment of the coverage of deaths of older adults in the Social Security Administration's Death Master File (DMF), this research note compares age-specific death counts from 1960 to 1997 in the DMF with official counts tabulated by the National Center for Health Statistics, the most authoritative source of death information for the U.S. population. Results suggest that for most years since 1973, 93 percent to 96 percent of deaths of individuals aged 65 or older were included in the DMF.
In this article we explore the extent of and reasons for attrition in the New Beneficiary Survey (NBS) between the first interview in 1982 and the followup interview in 1991. We examine a variety of potential determinants of attrition, separating the probability of attrition due to death from a refusal to be interviewed. Because the NBS sample is drawn from and linked to Social Security administrative records, information on mortality as a cause of attrition is exact. Hence, we are able to examine differences in the patterns and predictors of attrition due to these two causes of attrition and differences between attrition among retired and disabled workers.
Who Is "62 Enough"? Identifying Respondents Eligible for Social Security Early Retirement Benefits in the Health and Retirement Study
Workers are not instantly eligible for Social Security retirement benefits on their 62nd birthdays, nor can they receive benefits in the month they turn 62. This note discusses how well researchers can do using data from the Health and Retirement Study (HRS) to identify respondents old enough to receive and report early Social Security retirement benefits. It shows that only some workers aged 62 at the time of an HRS interview will be "62 enough" to have received a Social Security benefit and reported it in the survey.
This article describes the development of SSA's administrative records database for the Project NetWork return-to-work experiment targeting persons with disabilities. The article is part of a series of papers on the evaluation of the Project NetWork demonstration. In addition to 8,248 Project NetWork participants randomly assigned to receive case management services and a control group, the simulation identified 138,613 eligible nonparticipants in the demonstration areas. The output data files contain detailed monthly information on Supplemental Security Income (SSI) and Disability Insurance (DI) benefits, annual earnings, and a set of demographic and diagnostic variables. The data allow for the measurement of net outcomes and the analysis of factors affecting participation. The results suggest that it is feasible to simulate complex eligibility rules using administrative records, and create a clean and edited data file for a comprehensive and credible evaluation. The study shows that it is feasible to use administrative records data for selecting control or comparison groups in future demonstration evaluations.
The Health and Retirement Study (HRS is a major longitudinal study designed for scientific and policy researchers for study of the economics, health, and demography of retirement and aging. This note describes the data from SSA records that have been released for linking to HRS data, linkage rates resulting from the consent process, and subgroup patterns in linkage rates.
Who Is "62 Enough": Identifying Eligibles for Social Security Early Retirement in the Health and Retirement Study
Either the normal retirement age (NRA) or the earliest eligibility age (EEA) for Social Security retirement benefits would be increased under many proposals for Social Security reform. As a consequence, research interest in who retires at early ages and the potential effects of an increase in the NRA or EEA has grown. This note discusses how well researchers can do using data from the Health and Retirement Study in identifying the pool of respondents who could have received early Social Security retirement benefits.
The Health and Retirement Study (HRS) is a major longitudinal study designed for scientific and policy researchers for study of the economics, health, and demography of retirement and aging. The primary HRS sponsor is the National Institute of Aging, and the project is being conducted by the Survey Research Center of the Institute for Social Research at the University of Michigan. Several agencies, including the Social Security Administration, are supporting the project. This is the second paper describing SSA's data support for the HRS. It describes the data from SSA records that have been released for linking to HRS data, linkage rates resulting from the consent process, and subgroup patterns in linkage rates.
The Accuracy of Survey-Reported Marital Status: Evidence from Survey Records Matched to Social Security Records
Many researchers have concluded that, in surveys, divorced persons often fail to report accurate marital information. In this paper, I revisit this issue using a new source of data—surveys exactly matched to Social Security data. I find that divorced persons frequently misreport their marital status, but there is evidence that the misreporting is unintentional. A discussion of possible improvements in surveys is presented. Implications for the study of differential mortality and the study of poverty among aged women are discussed.
This article describes the statistical development of the geographic coding system used to identify worker location for the Continuous Work History Sample. The new system—which is planned for implementation for data year 1993—will provide more accurate geographic distributions of workers within a residence concept than the old system could provide within an employer location concept. The article also presents the results of a pilot study that tested the operational aspects of the new system. The results provide some preliminary estimates of the effect of the revised codes on the geographic distribution of workers.
Sampling Variance Estimates for SSA Program Recipients From the 1990 Survey of Income and Program Participation
This working paper includes two interrelated papers presented at the annual meeting of the American Statistical Association in August 1991. The papers outline the central ideas and the progress to date associated with the development of a new microsimulation model for program analysis at the Social Security Administration (SSA). The first paper, Rationale for a SIPP-Based Microsimulation Model of SSI and OASDI, relates the analytical potential of the proposed model to data development efforts intended to overcome specific information gaps. It also suggests areas in which the model can enrich SSA's ability to address issues specifically related to either the Supplemental Security Income or Old-Age, Survivors, and Disability Insurance programs or issues requiring comparative analysis of both programs. The second paper, Implementing an SSI Model Using the Survey of Income and Program Participation, describes progress on a preliminary version of the model focusing on the SSI program. It includes a brief description of the model, presentation and discussion of initial results, and comparisons with other studies.
Reflections on the Income Estimates from the Initial Panel of the Survey of Income and Program Participation (SIPP)
The Survey of Income and Program Participation (SIPP) represents a major effort on the part of the Federal statistical community to improve the quality and comprehensiveness of information on the economic resources of the household sector and to permit a more accurate portrayal of the impact of government tax and transfer programs on the economic status of the population.
This paper will not offer a comprehensive and definitive statement on the quality of SIPP income data. Neither the time nor resources available to the author, nor indeed, the state of SIPP data products, would permit making such a statement. However, enough information is available to offer a tentative interpretation of important aspects of the income data available from the first SIPP panel. Two broad themes will be touched upon. Since it is generally believed that the major technical defect of income surveys is the substantial tendency to underidentify the sources and amounts of income received by the population, the issue of the completeness of the SIPP money income estimates will be the central issue. A second important aspect of income data has to do with its suitability for analytic purposes.
Development and Evaluation of a Survey-Based Type of Benefit Classification for the Social Security Program
A Note on Sampling Variance Estimates for Social Security Program Participants From the Survey of Income and Program Participation
It is well-known that for most purposes income size distribution data collected in household surveys are far from ideal. The problems with those data can be separated into two types: the data items that are collected, and the accuracy of the data collected. Usually, although there are important exceptions, the income data collected are confined to cash income before taxes, thus ignoring the effects of both taxes and noncash income of all types. Also, the income estimates usually are for one year, which often is not the best accounting period for analysis. Furthermore, there usually is a lack of adequate detail by income type, and the data ordinarily are not sufficiently detailed to adjust for changes in the composition of the family unit during the income accounting period.
An Example of the Use of Statistical Matching in the Estimation and Analysis of the Size Distribution of Income
This paper discusses the use of statistical matching in the estimation and analysis of the size distribution of family unit personal income. Statistical matching is a relatively new technique that has been used to combine, at the single observation level, data from two different samples, each of which contains some data items that are absent from the other file. In a statistical match, the information brought together from the different files ordinarily is not for the same person but for similar persons; the match is made on the basis of similar characteristics. In contrast, in an "exact" match, information for the same person from two or more files is brought together using personal identifying information.