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The organization, delivery, and financing of health care services in the United States is complex, comprising an interdependence of the private and governmental sectors of the economy. This pluralistic health care economy, with its pragmatic mix of public and private organizations, has produced a wide range of databases that help to monitor the health of the nation.

Health care spending has risen rapidly in the United States, claiming a larger and larger share of national resources. In 1965, $41.1 billion was spent for health care, constituting 5.7 percent of the gross domestic product (GDP). In 1998, health care expenditures totaled $1.1 trillion, an average of $4,094 per person and 13.5 percent of the GDP. Almost 11.5 million civilians—8.8 percent of employed civilians—were employed in the health services industry in 1998.

The growth of the health care industry in the United States has been accompanied by significant achievements in public health, including advances in prevention and, since 1950, significant declines in death rates for cardiovascular diseases, diseases of the heart, and stroke. There has been great success in monitoring these and other morbidity and mortality trends through the growth and development of our health information systems.

There is general agreement that data are needed to monitor the health of the nation; to plan and develop better health services; to deliver those services in an effective, efficient, and equitable manner; to measure their effectiveness, to make decisions on resource allocation; and to conduct research. Data also are needed to facilitate effective policymaking, planning, management, and evaluation. The federal government needs a variety of data to support its role in improving health and medical care delivery systems throughout the nation. State and local government agencies also play key roles in disease prevention, delivery of health services, and health planning and evaluation, all of which require timely and reliable health statistics. Private organizations of health professionals, health-service providers, health insurance, and many others have important interests in the collection and use of health data.

The statistical and information needs of the American pluralistic health care economy have grown enormously in the years since the enactment of the Medicare and Medicaid programs in 1965. The rapid growth of public and private health insurance, the expansion of the health care industry, and the concomitant public health, medical, and technological advances to meet the needs of a growing population have contributed to the growth of health information systems. Trends that require close monitoring include the aging of the population, the emergence of the chronic illnesses as the leading causes of morbidity and mortality, and the growing health care needs of subpopulation groups, including minorities, the uninsured, immigrants, and persons with disabilities and low incomes.

HEALTH SURVEYS AND ORGANIZATIONS

Health surveys go back to the Hagerstown morbidity studies conducted by the U.S. Public Health Service in the early 1920s. However, sample surveys did not become dominant until the rise of probability sampling in the 1930s. The U.S. Public Health Service conducted the first National Health Survey in 1935–1936, funded by the Works Projects Administration (WPA). In 1953 the National Opinion Research Center began a series of surveys, separated by five-year intervals, on consumers' use of medical care, the degree of health insurance protection, and expenditures for care.

In October 1953 a subcommittee of the U.S. National Committee on Vital and Health Statistics recommended that a national health survey be established on a permanent basis. The National Health Survey Act of 1956 called for a continuing survey and special studies on the nation's health. It also provided for studying methods and survey techniques for obtaining this statistical information and for disseminating the results of these surveys and studies. The National Health Survey, later renamed the National Health Interview Survey (NHIS), began in 1957. In 1960 the National Center for Health Statistics (NCHS) was created by combining the National Health Survey and the National Office of Vital Statistics. Responsibility for vital statistics had been transferred to the U.S. Public Health Service from the Bureau of the Census.

The NCHS is the federal government's principal health statistics agency. The NCHS congressional mandate addresses the full spectrum of health concerns from birth to death, including overall health status; environmental, social, and other health hazards; the onset and diagnosis of illness and disability; health resources; and the use, cost, and financing of health care. The NCHS also has the mandated responsibility for assisting state and local health agencies in meeting their costs of data collection.

Many other federal agencies have responsibilities for health-data collection. For example, within the U.S. Department of Health and Human Services (USDHHS), thirteen agencies have such responsibilities, including the National Institutes of Health (NIH), the Centers for Disease Control and Prevention (CDC), the Substance Abuse and Mental Health Services Administration (SAMHSA), the Office of the Assistant Secretary for Planning and Evaluation (OASPE), the Agency for Health Care Policy and Research (AHCPR), the Health Care Financing Administration (HCFA), and the Health Resources Services Administration (HRSA). In addition, other federal agencies have health statistic operations in support of their programs, including the Bureau of the Census, the Bureau of Labor Statistics, and the Departments of Agriculture, Defense, Commerce, Transportation, and Veterans Affairs.

The production of health statistics is clearly a multiorganizational responsibility. No one agency or organization can produce all of the health statistics needed to monitor the health of the nation. Following is a summary of the major types of health statistics, who produces them, and how they contribute to monitoring the health of the nation.

VITAL STATISTICS

Birth, death, and fetal-death statistics are kept through the National Vital Statistics System of the NCHS. This program, together with the Bureau of the Census decennial census, immigration, and emigration data, provide information on the dynamics and growth of the population. This information is used in making population projections, in fertility analysis, in planning for health services, for projecting school needs, and for other purposes. It is essential in the teaching and application of demography, epidemiology, sociology, medicine, and public health.

The historical roots of the vital statistics registration system go back to the earliest American settlements, when colonies such as Massachusetts and Virginia, following the English custom, required that records be kept of christenings, weddings, and burials. Lemuel Shattuck was the leading proponent of registration. He demonstrated that the health of the residents of the city of Boston was deteriorating, as measured by mortality levels. The Report of the Sanitary Commission of Massachusetts, authored by Shattuck, recommended the creation of a state board of health based on complete registration and vital statistics. However, it was not until 1933 that all states had similar registration programs.

Vital statistics are provided through state-operated registration systems. Standard forms for the collection of data and model procedures for the uniform registration of events are developed and recommended for use through cooperative activities of the states and the NCHS. The NCHS shares the costs incurred by the states in providing vital statistics for national use. Additional programs related to the National Vital Statistics System include the Linked Birth and Infant Death Data Set, the National Maternal and Infant Health Survey, the National Mortality Followback Survey, and the National Death Index. The introduction of the National Death Index (NDI), a computerized index of death record information beginning with 1979 deaths, has made enormous contributions to more efficient epidemiologic and health studies. Researchers can go to one source, the NCHS, to obtain mortality information on their study participants. Prior to the establishment of the NDI, each state had to be contacted separately for such information.

The vital statistics program is generally regarded as a successful program, providing full counts of births and deaths at the local, state, and federal geographic levels. Except for the important issue of timeliness, the reports emanating from the vital statistics program have done an excellent job of meeting the demands of users. The availability of data electronically has helped to improve the timeliness of vital-statistics data, thereby enhancing the usefulness of the data.

PUBLIC HEALTH SURVEILLANCE

Public health surveillance is defined as the "ongoing systematic collection, analysis, and interpretation of data on specific health events affecting a population, closely integrated with the timely dissemination of these data to those responsible for prevention and control" (Thacker et al. 1996, p.633). A feature of surveillance is the ability to identify individuals and groups of individuals for further action on prevention and treatment. The CDC and other federal agencies are involved in the collection of surveillance data, including, but not limited to, the following:

• The CDC operates the National Notifiable Disease Surveillance System. Physicians, laboratory personnel, and other health care providers are required by state law to report weekly all cases of health conditions, mainly infectious in origin, that are specified as being notifiable. The Council of State and Territorial Epidemiologists determines which notifiable conditions should be reported from state health departments to the CDC.
• The National Institute of Occupational Safety and Health has maintained the National Traumatic Occupational Fatalities Surveillance System, a sentinel health event verification system for occupational risk. It is based on information taken from death certificates.
• The Food and Drug Administration conducts post-marketing surveillance of adverse reactions to drugs.
• The National Cancer Institute conducts the Surveillance, Epidemiology, and End-Results (SEER) Program that includes eleven population-based registries in the United States. It provides data on all residents diagnosed with cancer during the year, as well as follow-up information on all previously diagnosed patients.
• The CDC conducts the Behavioral Risk Factor Surveillance System (BRFSS), a telephone survey conducted in each of the fifty states that provides data on health behaviors. Questions can be added to the survey by individual states.
• The CDC has developed the Pregnancy Assessment Monitoring System (PRAMS) to collect information on maternal behaviors that occur before, during, and shortly after pregnancy.
• The Consumer Product Safety Commission conducts surveillance on product-related injuries.

Surveillance data vary in their quality, are often incomplete and unrepresentative, and they may vary in sensitivity and specificity. Although the current programs provide essential data to monitor the incidence of communicable diseases and some chronic diseases, the system also relies on voluntary physician reporting, which has been demonstrated to be variable and inconsistent. States differ in their authority to require physician reporting. Development of greater standardization in reporting from state to state and obtaining improved physician cooperation are both areas that need further exploration.

Population-based registries and national sample surveys have also been used for surveillance purposes. Registries are established to identify cases through several sources (schools, hospitals, laboratories). Registries require extensive confirmation of cases, which leads to longer lag times between a health event and the reporting of the event. NCI's SEER program covers about 10 percent of the U.S. population and provides data that are used to monitor long-term trends of cancer incidence and mortality. Currently, approximately thirty states have population-based registries, but they may be limited by both under-registration and selection bias.

HEALTH STATUS, HEALTH CARE UTILIZATION, AND COSTS

Statistics abound on health status and the use of medical care services at the federal, state, and local levels. The National Health Interview Survey (NHIS) and the National Health and Nutrition Examination Survey (NHANES) are the major national surveys for assessment of health status in the United States. Both are sponsored by the NCHS. The NHIS is a primary source of information on the health of the civilian, noninstitutionalized population of the United States. Conducted continuously since 1957, it provides national data on the annual incidence of acute illness and accidental injuries, the prevalence of chronic conditions and impairments, the extent of disability, the utilization of health care services, and other health-related topics. To provide data on special topic areas in addition to the basic NHIS data, extensive supplements have been conducted annually. Topics of coverage in the supplements vary from year to year. For example, in 1995 the supplements included questions on the following topics: immunization, disability, followback of persons with disabilities interviewed in the prior year, family resources (access to care, health care coverage, income, and assets), year 2000 objectives, tobacco use, nutrition, clinical preventive services, physical activity and fitness, and AIDS (acquired immunodeficiency syndrome) knowledge and attitudes. The NHIS sample design includes about 40,000 households interviewed, resulting in a sample of about 102,000 individuals, with oversampling of black and Hispanic persons.

The National Health and Nutrition Examination Survey (NHANES) was established in 1971 to collect the kind of health data best obtained by direct physical examinations and physiological and biochemical measurements. The NHANES is the cornerstone of the National Monitoring and Related Research Program, providing data needed for nutrition monitoring, food fortification policy, establishing dietary guidelines, and assessing government programs and initiatives such as the Healthy People 2000 objectives of the USDHHS. In the past, researchers sometimes had to wait as long as ten years after data collection before gaining access to data based on the entire six-year sample. The NHANES is now a continuing, annual survey, linked to the NHIS, and data are being collected from a representative sample of the U.S. population every year.

The NHIS and the NHANES are only two of the many national federal surveys that collect data on heath status, medical care utilization, and insurance coverage. Other important surveys that collect similar data, as well as data on medical care expenditures, include the following:

• The National Immunization Survey (NIS) is a continuing nationwide telephone sample survey that gathers data on children 19 to 35 months of age. In 1997, data were obtained for 32,742 children to provide estimates of vaccine-specific coverage for areas considered to be high risk for under-vaccination.
• The Medical Expenditure Panel Survey (MEPS) conducted by the Agency for Healthcare Research and Quality (AHRQ) is a study of approximately 9,000 households. MEPS is a subsample of NHIS participants, providing health status and other data to enhance analytical capacity. Use of NHIS data, in concert with the data collected in the MEPS, provides the capacity for longitudinal analysis. Each sample panel is interviewed a total of five times over thirty months to yield annual use and expenditure data for two calendar years. The MEPS household component reflects an oversampling of households with Hispanics and blacks. MEPS also has an institutional component.
• The National Household Survey on Drug Abuse (NHSDA), conducted by SAMSHA, focuses on the incidence, prevalence, consequences, and patterns of substance use and abuse. In 1997 the NHSDA was expanded from 18,000 respondents to about 25,000 respondents to generate estimates for the nation and for two states (California and Arizona). In 1999 the NHSDA was further expanded to 70,000 respondents to generate estimates for all fifty states.
• The Survey of Mental Health Organizations, conducted by SAMSHA, is a biennial inventory of mental health organizations and general hospital mental health services.
• The Medicare Current Beneficiary Survey (MCBS), conducted by the Health Care Financing Administration (HCFA), is an ongoing rotating panel survey of approximately 12,000 aged and disabled Medicare beneficiaries, consisting of four overlapping panels of Medicare beneficiaries surveyed each year. Each panel contains a national representative panel of beneficiaries who are interviewed twelve times to collect three complete years of utilization data. The survey provides comprehensive data on health and functional status, use of medical services, covered and noncovered health care expenditures, and health insurance for Medicare beneficiaries.
• The National Health Care Survey (NHCS) is a family of NCHS provider-based surveys that measure the utilization of health services. Included are hospitals (National Hospital Discharge Survey), physicians (National Ambulatory Medical Care Survey), emergency and outpatient departments (National Hospital Ambulatory Medical Care Survey), ambulatory care centers (National Survey of Ambulatory Surgery), nursing homes (National Nursing Home Survey), and health agencies providing home health care services and hospice care (National Home and Hospice Care Survey).
• The National Survey of Family Growth (NSFG) is a periodic survey of women 15 to 44 years of age. The purpose of the survey is to provide national data on factors affecting birth and pregnancy rates, adoption, and maternal and infant health. In 1995, for the first time, the sample was obtained from households that had been interviewed in the NHIS. A total of 10,847 women were interviewed, and Hispanic and black women were oversampled. Cycle six of the NSFG will include a sample of men for the first time.
• The Healthcare Cost and Utilization Project (HCUP), conducted by the AHRQ, consists of the State Inpatient Databases (SID) and the Nationwide Inpatient Sample (NIS). The SID contains all hospitals and all discharges from twenty-two participating states. The AHCPR receives the data from each statewide data organization, processes the data into a uniform format, and then returns the uniform SID files to the statewide data organization. The NIS database contains a sample of hospitals selected from SID. The NIS can be used to produce national estimates, regional estimates, and state estimates for participating states.
• The Current Population Survey (CPS) is a monthly sample survey of about 50,000 households conducted by the U.S. Bureau of the Census for the Bureau of Labor Statistics. The CPS is the primary source of information on labor force characteristics of the U.S. population. Monthly estimates from the CPS include employment, unemployment, earnings, hours of work, and other indicators. The annual March supplement produces national and state estimates on health insurance coverage, including private health insurance, Medicare, Medicaid, CHAMPUS, and military health care.

PRIVATE SECTOR DATA COLLECTION SYSTEMS

In addition to the federal health statistics surveys and the programs briefly discussed above, the fifty states and the private sector maintain data systems and conduct many surveys of hospitals, health professionals, and health care organizations. The private health sector includes organizations of health-service providers, health professionals, health-insurance payers, consumers, industry, and private philanthropy. The following private organizations maintain health-data systems relating to their specific areas of interest: The Alan Guttmacher Institute conducts an annual survey of abortion providers; the American Association of Colleges of Osteopathic Medicine compiles data on various aspects of osteopathic medical education; the American Association of Colleges of Pharmacy compiles data on student enrollment and types of degrees conferred; the American Association of Colleges of Podiatric Medicine compiles data on schools and enrollment; the American Dental Association conducts annual surveys of predoctoral dental educational institutions, including information on student characteristics, financial management, and curricula; the Association of American Medical Colleges collects information on student enrollment in medical schools; the Association of Schools and Colleges of Optometry compiles data on the various aspects of optometric education; the Association of Schools of Public Health compiles data on the twenty-eight schools of public health in the United States; and the National League for Nursing conducts an annual survey of schools of nursing.

The American Hospital Association conducts an annual survey of all hospitals and compiles information on characteristics of the facilities and services provided, admissions, and expenses and revenues. The American Medical Association maintains a physician masterfile on almost every physician in the United States. Inter Study compiles data on health maintenance organizations. Many national and state data collection activities are conducted by these private organizations, but their scope and quality varies.

HEALTHY PEOPLE 2000

A relatively recent and important development in monitoring the health of the nation has been the identification of broad goals and detailed objectives, described in Healthy People 2000: National Health Promotion and Disease Prevention Objectives, published by the U.S. Department of Health and Human Services in 1991, and in subsequent reports. The targets contained in Healthy People 2000 were developed between 1987 and 1990 through an extensive consultative and hearings process conducted and managed by the U.S. Public Health Service in partnership with the Institute of Medicine of the National Academy of Sciences. To provide guidance to the effort, a national consortium was formed that included the principal health officials in the fifty states and representatives of more than three hundred professional and voluntary national membership organizations.

Three broad goals were identified for the program: (1) increase the span of healthy life for Americans, (2) reduce health disparities among Americans, and (3) achieve access to preventive services for Americans. To foster accomplishment of these goals, Healthy People 2000 also set forth three hundred measurable objectives to be accomplished by the year 2000 in twenty-two priority areas of health promotion, health protection, and clinical preventive services. In addition, objectives were established for improving surveillance and data systems at national, state, and local levels to target interventions to areas of greatest need. The range of topics covered by the objectives is extensive, and includes the following: (1) personal behavior and risk factors such as physical fitness and activity, nutrition, tobacco, and alcohol and other drugs; (2) psychosocial factors such as mental health and violent and abusive behavior; (3) the physical environment, including unintentional injuries, occupational safety and health, environmental health, and food and safety; (4) infectious diseases, including HIV (human immunodeficiency virus) infection and sexually transmitted diseases; (5) reproductive and infant health, including family planning and maternal and infant health; (6) chronic diseases such as heart disease and stroke, cancer, diabetes, oral health problems, and chronic disabling conditions; and (7) services and protection, including educational and community-based programs, as well clinical preventive services.

Based on 319 unduplicated objectives, 15 percent of the objectives reached or surpassed the year 2000 targets by the end of 1999. At this point, progress toward the targets had been made for another 44 percent of the objectives, 18 percent showed movement away from the target, 6 percent showed mixed results, and 3 percent showed no change from the baseline. The remaining objectives had no data with which to evaluate progress.

The national objectives in Healthy People 2000 have provided motivation for the continued development of public health assessment and monitoring of the nation's health efforts at the national, state, and local levels. This effort has led to the development of Healthy People 2010, the nation's prevention agenda for the first decade of the twenty-first century. It contains two broad goals— to increase the years and quality of healthy life and to eliminate health disparities among Americans, especially minorities. The two goals are supported by 467 objectives, grouped into 28 focus areas with specific numerical targets. Data for the baselines and to monitor progress in reaching these targets come from the National Vital Statistics Program, the National Health Interview Study, the National Health and Nutrition Examination Survey, and the Behavioral Risk Factor Surveillance System, and others data systems.

CONCLUSIONS

A variety of health data and information systems are now available in the United States to monitor the health of the nation. This information base must continue to be available to allow the monitoring of trends and the detection of changes or aberrations in the economic, social, or health characteristics of the nation. The appropriate federal role is to produce national data useful for these purposes, as well as to provide norms to which state and local data can be compared. The data must be of high quality, produced in a timely manner, and relevant to issues of the day.

As the nation moves closer to the objective of a national, systematic approach to meeting the information needs for monitoring the health of the nation, an effort must also be made to coordinate data-collection activities, both within the federal establishment and between the government and the private sector. This will avoid unnecessary and costly duplication and encourage comparability of information collected by different systems. These health information systems are essential to meet the multiple needs of many programs and organizations in the twenty-first century.

DOROTHY P. RICE

(SEE ALSO: Biostatistics; Certification of Causes of Deaths; Community Health Report Cards; Epidemiology; Field Survey; Healthy People 2010; Information Technology; Mortality Rates; National Center for Health Statistics; National Death Index; National Health Surveys; Notifiable Diseases; Registries; Reporting, Mandatory; Sampling; SEER Program; Statistics for Public Health; Surveillance; Surveys)