Technical Appendix 
Data in this report are based on the combined samples for the second year of the 1996 panel of the Medical Expenditure Panel Survey Household Component (MEPS HC) and the first year of the 1997 MEPS HC. MEPS is cosponsored by the Agency for Healthcare Research and Quality (AHRQ) and the National Center for Health Statistics (NCHS).  The focus of the MEPS HC is to collect detailed data on demographic characteristics, health conditions, health status, use of medical care services, charges and payments for those services, access to care, health insurance coverage, income, and employment of the U.S. civilian noninstitutionalized population. In other components of MEPS, data are collected on the use, charges, and payments reported by providers (Medical Provider Component) and the supply side of the insurance market (Insurance Component).
Survey Design
The sample for the 1996 MEPS HC was selected from respondents to the 1995 National Health Interview Survey (NHIS), and the sample for the 1997 MEPS HC was selected from the 1996 NHIS. NHIS, which is conducted by NCHS, provides a nationally representative sample of the U.S. civilian noninstitutionalized population and reflects an oversampling of Hispanics and blacks.
The MEPS HC collects data through an overlapping panel design. In this design, data are collected through a precontact interview that is followed by a series of five rounds of interviews over a period of 21/2 years. Interviews are conducted with one member of each family, who reports on the health care experiences of the entire family. Two calendar years of medical expenditure and utilization data are collected in each household and captured using computer-assisted personal interviewing (CAPI). This series of data collection rounds is launched again each subsequent year on a new sample of households to provide overlapping samples of survey data that will provide continuous and current estimates of health care expenditures. 
The estimates of total expenditures in Tables 1-4 are based on 32,636 sample persons.  They are weighted to develop population estimates for a total of 271,278,585 persons who were in the U.S. civilian noninstitutionalized population for part or all of 1997.  For persons who were in the target population for the full year, all expenditures from January 1 through December 31, 1997, were included in the estimates.  People with part-year information include newborns, people who died during the year, and people who resided in an institution, were in the military, or lived outside the country for part of the year.  Expenditures for deceased persons were measured for the period from January 1 through the date of death, while those for newborns were measured from the date of birth through December 31. Expenses incurred during periods of full-time active-duty military service, institutionalization, or residency outside the country were not included. 
This report provides estimates of expenditures in 1997 for the treatment of conditions that were reported to be attributable to an injury.  The estimates include expenditures for conditions associated with injuries that occurred in 1997 as well as in prior years. Expenditures refer to payments for health care services, including out-of-pocket payments and payments by private insurance, Medicaid, Medicare, WorkersÕ Compensation, and other sources.  Ambulatory visits to medical providers in office and hospital settings, hospital inpatient care, home health care, and prescribed medicines are included in total expenditures, while payments for over-the-counter drugs, alternative care services, and telephone contacts with medical providers are not included.  In contrast to other reports containing MEPS expenditure estimates, expenses for durable medical equipment and other miscellaneous items (eyeglasses, contact lenses, ambulance services, orthopedic items, hearing devices, prostheses, bathroom aids, medical equipment, disposable supplies, and other miscellaneous items or services) are also excluded because it was not possible to determine from the survey questions which of these expenses were associated with injuries.
The estimates were developed using information collected in the conditions and medical events sections of the MEPS questionnaire (www.meps.ahrq.gov/survey.htm#hcsurveyinstrument).  In the conditions section, respondents were asked to identify medical conditions that bothered sample persons during the period covered by the interview and identify conditions that were due to an injury.  In the medical events sections, which collect information about ambulatory visits, inpatient hospitalizations, dental care, home health care, and prescribed medicines, respondents were asked to identify the conditions that were associated with each reported medical event.  This information was used to link medical events to associated injury-related conditions. Estimates of expenditures for these events were based on a combination of data obtained from sample personsÕ medical providers in the MEPS Medical Provider Component (used as first priority where available), the medical events sections of the MEPS HC, and imputation procedures for missing data. For detailed information on the MEPS sample design for Panel 1, see Cohen (1997).  For detailed information on the MEPS sample design for Panel 2, see Cohen (2000). For information on response rates and estimation procedures see the Documentation File for HC-020 (http://www.meps.ahrq.gov/pubdoc/h20doc.pdf). 
In the report, expenses are shown by selected population characteristics, including age, sex, race/ethnicity, health insurance status, and poverty status. (Definitions of these terms are given below.) In addition to total expenses by these characteristics, estimates on per capita expenses and spending for persons with expenses are provided. The per capita estimates were computed as the total injury-related expenses for a particular group divided by the total population of that group. The average number of conditions per injury episode was 1.04, indicating that the overwhelming majority of injuries were associated with only one condition. The standard errors for the estimates in this report are shown in Tables A-F.
Definitions of Terms
Type of Service
The types of service shown in Figures 1 and 2 are:
¥	Hospital inpatient servicesÑThis category includes room and board and all hospital diagnostic and laboratory expenses associated with the basic facility charge, payments for separately billed physician inpatient services, and some emergency room expenses incurred immediately prior to inpatient stays. It excludes expenses for hospital discharges that did not involve an overnight stay, which are classified as ambulatory expenses.
¥	Ambulatory servicesÑThis category includes expenses for visits to medical providers seen in office-based settings or clinics, hospital outpatient departments, emergency rooms (except some visits resulting in an overnight hospital stay), and clinics owned and operated by hospitals. It also includes expenses for events reported as hospital admissions without an overnight stay.
¥	Prescribed medicinesÑThis category includes expenses for all prescribed medications that were initially purchased or refilled during 1997, as well as expenses for diabetic supplies (some of which may have been purchased without a prescription).
¥	Dental servicesÑThis category covers expenses for any type of dental care provider, including general dentists, dental hygienists, dental technicians, dental surgeons, orthodontists, endodontists, and periodontists.
¥	Home health servicesÑThis category includes expenses for care provided by home health agencies and independent home health providers. Agency providers accounted for a large majority of the expenses in this category.
Source of Payment
The sources of payment shown in Figures 3 and 4 are classified as follows:
¥	Out-of-pocketÑThese are expenses paid by the user or other family member.
¥	Private insuranceÑThis category includes payments made by insurance plans covering hospital and medical care (excluding payments from Medicare, Medicaid, and other public sources). Payments from Medigap plans or CHAMPUS and CHAMPVA (Armed-Forces-related coverage) are included. Payments from plans that provide coverage for a single service only, such as dental or vision coverage, are not included.
¥	MedicareÑMedicare is a federally financed health insurance plan for the elderly, persons receiving Social Security disability payments, and most persons with end-stage renal disease. Medicare Part A, which provides hospital insurance, is automatically given to those who are eligible for Social Security. Medicare Part B provides supplementary medical insurance that pays for medical expenses and can be purchased for a monthly premium.
¥	MedicaidÑMedicaid is a means-tested government program jointly financed by Federal and State funds that provides health care to those who are eligible. Program eligibility criteria vary significantly by State, but the program is designed to provide health coverage to families and individuals who are unable to afford necessary medical care.
¥	WorkersÕ CompensationÑWorkersÕ Compensation is a system, required by law, of compensating workers injured or disabled in connection with work.  This system establishes the liability of an employer for injuries or sickness that arise over and in the course of employment.  The benefits under this system generally include hospital and other medical payments and compensation for loss of income.  
¥	Other sourcesÑThis category includes payments from the Department of Veterans Affairs (except CHAMPVA); other Federal sources (Indian Health Service, military treatment facilities, and other care provided by the Federal Government); various State and local sources (community and neighborhood clinics, State and local health departments, and State programs other than Medicaid); various unclassified sources (e.g., automobile, homeownerÕs, or other liability insurance, and other miscellaneous or unknown sources); Medicaid payments reported for people who were not reported as enrolled in the Medicaid program at any time during the year; and private insurance payments reported for people without any reported private health insurance coverage during the year.
Population Characteristics
In general, population characteristics are measured as of December 31, 1997, or the last date that theÊsample person was part of the civilian noninstitutionalized population living in the United States prior to December 31, 1997.
Race/Ethnicity
Classification by race and ethnicity is based on information reported in MEPS for each family member. Respondents were asked if the race of the sample person was best described as American Indian, Alaska Native, Asian or Pacific Islander, black, white, or other. They also were asked if the sample personÕs main national origin or ancestry was Puerto Rican; Cuban; Mexican, Mexicano, Mexican American, or Chicano; other Latin American; or other Spanish. All persons whose main national origin or ancestry was reported in one of these Hispanic groups, regardless of racial background, are classified as Hispanic. The other race categories do not include Hispanic persons.
Comparisons by race/ethnicity are based on the following four race/ethnicity groups: white, black, Hispanic, and other. 
Health Insurance StatusÊ
Individuals under age 65 were classified into the following three insurance categories. 
¥	Any private health insuranceÑIndividuals with insurance that provides coverage for hospital and physician care at any time during the year (other than Medicare, Medicaid, or other public hospital/physician coverage) are classified as having private insurance. Persons with Armed-Forces-related coverageÑCHAMPUS/CHAMPVA (currently called TRICARE)Ñare also included because the number of sample persons in this group is small and this type of coverage is similar to private insurance. Insurance that provides coverage for a single service only, such as dental or vision coverage, is not included.
¥	Public coverage onlyÑIndividuals are considered to have public coverage only if they met both of the following criteria:
4	They were not covered by private insurance at any time during the year.Ê 
4	They were covered by one of the following public programs at any point during the year: Medicare, Medicaid, or other public hospital/physician coverage. 
¥	UninsuredÑThe uninsured are defined as persons not covered by Medicare, CHAMPUS/CHAMPVA, Medicaid, other public hospital/physician programs, or private hospital/physician insurance at any time during 1997. Individuals covered only by noncomprehensive State-specific programs (e.g., Maryland Kidney Disease Program, Colorado Child Health Plan) or private single-service plans (e.g., coverage for dental or vision care only, coverage for accidents or specific diseases) are not considered to be insured.
Individuals age 65 and over were classified into the following three insurance categories:
¥	Medicare only.
¥	Medicare and private insurance.
¥	Medicare and other public insurance.
Poverty Status
Each person was classified according to the total 1997 income of his or her family. Within a household, all individuals related by blood, marriage, or adoption were considered to be a family. Personal income from all family members was summed to create family income. Possible sources of income included annual earnings from wages, salaries, bonuses, tips, and commissions; business and farm gains and losses; unemployment and WorkersÕ Compensation; interest and dividends; alimony, child support, and other private cash transfers; private pensions, individual retirement account (IRA) withdrawals, Social Security, and veteransÕ payments; Supplemental Security Income and cash welfare payments from public assistance, Aid to Families with Dependent Children, and Aid to Dependent Children; gains or losses from estates, trusts, partnerships, S corporations, rent, and royalties; and a small amount of other income. Poverty status is the ratio of family income to the 1997 Federal poverty thresholds, which vary by family size and age of the head of the family. The categories are:Ê
¥	PoorÑThis refers to persons in families with income at or less than the poverty line.
¥	Near-poorÑThis refers to persons in families with income over the poverty line through 125 percent of the poverty line.  
¥	Low incomeÑThis category includes persons in families with incomes over 125 percent through 200 percent of the poverty line.
¥	Middle incomeÑThis category includes persons in families with income over 200 percent through 400 percent of the poverty line.
¥	High incomeÑThis category includes persons in families with income over 400 percent of the poverty line.
 Significance Testing
Tests of statistical significance were used to determine whether the differences between populations exist at specified levels of confidence or whether they occurred by chance. Differences were tested using Z-scores having asymptotic normal properties at the 0.05 level of significance. However, each individual significance test was conducted at the 0.05 level, which does not control the overall Type I error level at 0.05. 
Rounding
Estimates presented in the tables are rounded as follows:
¥	Percentages are rounded to the nearest 0.1 percentage point. 
¥	Mean and median expenditures are rounded to the nearest dollar.
¥	Total expenditures are rounded to the nearest million dollar unit. 
Some of the estimates for population totals of subgroups presented in the tables will not add exactly to the overall estimated population total as a consequence of rounding.