This alphabetical list provides an explanation of terms that may require clarification. The definitions are taken from original surveys or cited publications as closely as possible, to convey the original authors' perspectives. Surveys that are mentioned in this Glossary are explained in more detail in Surveys.
ADL: See Activities of daily living (ADLs).
Activities of daily living (ADLs): The National Health Interview Survey (NHIS) asks questions to identify people who "need the help of other persons with personal care needs such as eating, bathing, dressing or getting around...(inside the) home." (Adams & Marano, 1995). These particular activities are termed activities of daily living.
The Survey of Income and Program Participation (SIPP) definition of ADL includes eating, bathing, dressing or getting around inside the home, but also specifies getting into and out of bed or a chair, and toileting. The SIPP asks about whether a person has difficulty with any of these ADLs (one of the criteria for disability) and whether a person needs assistance to do the activity (one of the criteria for severe disability).
The National Medical Expenditures Survey (NMES) definition is similar to the SIPP definition. The NMES describes ADLs as basic self-care tasks that include bathing, dressing, toileting, getting in and out of bed or a chair, feeding oneself, and walking across the room. A limitation in an ADL is defined as needing the help of another person or special equipment to perform the activity.(See also instrumental activities of daily living).
Activity limitation(s): On the National Health Interview Survey (NHIS), activity limitation refers to a long-term reduction in a person's capacity to perform the average kind or amount of activities associated with his or her age group. (See major activity for an explanation of the activities associated with each age group.) People are classified into one of four categories:
The NHIS classifies people as limited (groups 1-3) or not limited (group 4). People are not classified as limited in activity unless one or more chronic health conditions are reported as the cause of the activity limitation. (See also chronic health condition.)
The National Medical Expenditures Survey (NMES) considers adults 18 years and over to have an activity limitation if their health keeps them from working at a job, doing work around the house, or going to school or they are unable to do certain kinds or amounts of work, housework, or school work because of their health. For school-aged children between the ages of 5 and 17, activity limitations are defined by questions about attending or needing special schools or classes, and/or limitations in school or other activities because of an impairment or health problem. For young children under 5 years, activity limitation is defined by questions about limitation in play or other activities, due to an impairment or health problem.
Bed-disability days: From the NHIS, a bed-disability day is one during which a person stayed in bed for more than half a day because of illness or injury. Bed-disability days include work-loss and school-loss days actually spent in bed. Bed-disability days measure the effect of brief episodes of illness or injury as well as long-term or chronic disability.
CPS: See Current Population Survey in the Appendix for survey description.
Children with disabilities: The Individuals with Disabilities Education Act (IDEA) includes children with mental retardation, hearing impairments including deafness, speech or language impairments, visual impairments including blindness, serious emotional disturbance, orthopedic impairments, autism, traumatic brain injury, other health impairments, or specific learning disabilities. In order to qualify under IDEA, children must need special education and related services by reason of their disability.
Chronic health condition/chronic condition: On the NHIS, a condition that a respondent described as having persisted for three or more months is considered to be chronic. Other conditions are always classified as chronic no matter how long the person has had the condition.
For analyses based on the NMES, the term "chronic condition" is a general term that encompasses both chronic illness (the presence of long-term disease or symptoms, usually lasting three months or more) and chronic impairment (a physiological, psychological, or anatomical abnormality of bodily structure or function, including all losses or abnormalities, not just those attributable to active pathology).
Comorbidity: Comorbidity is the technical term for having more than one chronic condition or disorder at the same time.
Current Population Survey (CPS): See Appendix for survey description.
Diagnostic and Statistical Manual (DSM-III, DSM-III-R and DSM-IV): The Diagnostic and Statistical Manual classifies and describes mental disorders and their symptoms. Many current studies of mental illness and disability use DSM diagnoses to define the mental disorders.
Disabled worker: Under the Social Security definition, disabled workers are people under age 65 who receive benefits as part of the Old Age, Survivors and Disability Insurance (OASDI) program. They have been determined to be disabled under Social Security criteria (i.e., cannot engage in "substantial gainful activity.") They have also earned at least a certain minimum amount of wages in employment covered under Social Security in order to receive income from Social Security Disability Insurance (SSDI).
Disability: On the NHIS, disability refers to any long- or short-term reduction of a person's activity as a result of an acute or chronic condition.
On the SIPP, people age 15 and over were considered to have a disability if they met any the following criteria:
A person also was considered to have a disability if
Epidemiological Catchment Area (ECA) Survey: See Appendix for survey description.
ESEA: ESEA refers to the Elementary and Secondary Education Act, State Operated Programs, Chapter 1. Until 1995, ESEA was one of two major programs that provided states with financial assistance to educate school-age children and youth with disabilities. Now all federal assistance is provided under IDEA.
Functional activity or activities: The SIPP asked respondents about their ability to perform the following specific sensory and physical activities:
Difficulty in performing any of these functional activities is classified as a functional limitation in the SIPP.
The NHIS-D asked respondents about their ability to perform the following activities:
Inability to perform any of these activities is classified as a functional limitation.
Functional disability: The concept of functional disability was added to the Decennial Census in 1990, with a question about whether a person had a health condition that limited his or her ability to go outside the home alone or caused difficulty in taking care of personal needs such as bathing, dressing, or getting around inside the home. The question bears similarities to the SIPP concepts of functional activity and activities of daily living, but is not exactly equivalent.
On the NHIS-D, functional disability includes
Functional limitation(s): See functional activities.
IADL: See Instrumental activities of daily living (IADLs).
IDEA: IDEA stands for the Individuals with Disabilities Education Act, Part B Program. IDEA is now the major federal program that provides states with financial assistance to educate children and youth with disabilities. Before 1995, special education was also funded under ESEA.
Instrumental activities of daily living (IADLs): The NHIS collects information on people's need for assistance from others in performing instrumental activities of daily living (IADLs). The IADLs include: "doing everyday household chores, necessary business, shopping or getting around for other purposes." People who need assistance in activities of daily living (ADLs) were not asked about IADL.
On the SIPP, instrumental activities of daily living include: going outside the home, keeping track of money or bills, preparing meals, doing light housework, and using the telephone.
(See also activities of daily living).
Life expectancy: Life expectancy is an estimate of the average number of years of life remaining to a person at a particular age, based on a set of age-specific death rates, usually the mortality conditions existing at the time of the estimate.
Labor force: As used by the Bureau of the Census in the March Supplement of the Current Population Survey (CPS), the labor force includes people employed as civilians, currently unemployed, or in the Armed Forces during the survey week. People who are neither employed nor seeking employment are not included in the labor force (people engaged in housework, attending school, unable to work because of long-term physical or mental illness, persons who are retired or too old to work, seasonal workers in an off season, and voluntarily idle people).
Labor force participation rate (LFPR): The LFPR, which is the number of people in a given population that are in the labor force divided by the number of people in that population, is a primary measure in labor market analysis.
Major activity: In NHIS, people are classified in terms of the major activity usually associated with their particular age group. The major activities for the age groups are:
People ages 18-69 years who are classified as keeping house are also classified according to their ability to work at a job or business. (See activity limitation.)
Medical expenditures: The National Medical Expenditure Survey measures costs for medical care by totaling costs for hospital care, physician services, emergency room, dental services, vision aids, prescription drugs, medical equipment and home care.
Mental disorder: In the Epidemiological Catchment Area (ECA) studies, the presence of a mental disorder was determined by asking about a person's symptoms, using the Diagnostic Interview Survey (DIS). People whose symptoms met the criteria for diagnosis based on the American Psychiatric Association's Diagnostic and Statistical Manual (DSM-III or DSM-IIIR) were classified as having a mental disorder. (See also severe mental disorder.)
NCS: See National Comorbidity Survey in Appendix for survey description.
NHIS: See National Health Interview Survey in Appendix for survey description.
NHIS-D: See National Health Interview Survey in Appendix for survey description.
NHIS-MH: See National Health Interview Survey in Appendix for survey description.
NMES: See National Medical Expenditures Survey in Appendix for survey description.
National Alliance for Caregiving Survey: See Appendix for survey description.
National Comorbidity Survey: See Appendix for survey description.
National Health Interview Survey (NHIS): See Appendix for survey description.
National Health Interview Survey on Disability (NHIS-D): See National Health Interview Survey in Appendix for survey description.
National Health Interview Survey, Mental Health Supplement (NHIS-MH): See National Health Interview Survey in Appendix for survey description.
National Medical Expenditures Survey (NMES): See Appendix for survey description.
National Nursing Home Survey: See Appendix for survey description.
Non-institutionalized: Many estimates from federal surveys are based only on people who are not in institutions at the time of the survey, that is, the non-institutionalized people in the population. Institutions include correctional institutions, mental (psychiatric) hospitals, residential treatment centers, tuberculosis hospitals, chronic disease hospitals, homes for the aged, homes and schools for the mentally handicapped, homes and schools for the physically handicapped, homes for unwed mothers, homes for dependent and neglected children, training schools for juvenile delinquents, and detention homes for juveniles.
Non-severe disability: In the SIPP, people are classified as having a non-severe disability if they meet the criteria for disability, but do not meet the criteria for severe disability. For example, a person who has difficulties with activities of daily living (one of the criteria for disability) but who does not need personal assistance with activities of daily living, would be classified as having a non-severe disability (unless that person met other criteria for severe disability).
OASDI: See Old Age, Survivors, and Disability Insurance.
Old Age, Survivors and Disability Insurance (OASDI): This federally-administered program provides monthly benefits to retired and disabled workers and their dependents and survivors. Benefits are earned in employment covered under Social Security. The part of OASDI that provides benefits to workers on the basis on disability is called Social Security Disability Income (SSDI).
Perceived disability: In the NHIS-D, people were asked if they considered themselves to have a disability or are considered by others to have one. This reflects the definition of disability used in the Americans with Disabilities Act (ADA).
Personal assistance: In the NHIS core questionnaire, respondents are asked if they "need the help of other people" with personal care needs (activities of daily living) or handling other routine needs (instrumental activities of daily living). Those who answer affirmatively are categorized as needing personal assistance.
On the SIPP, respondents are first asked whether they have difficulty with any activities of daily living or instrumental activities of daily living. If they report difficulties, they are then asked a follow-up question about whether they need the help of another person to perform the activity, that is, the need for personal assistance.
Poverty: Poverty statistics presented in this report are based on a definition of poverty that was originally developed by the Social Security Administration and was linked to the cost of food. The poverty index is based on income thresholds that vary by family size and composition, and the thresholds rise each year by the same percentage as the Consumer Price Index. For example, the average poverty threshold for a family of four was $14,335 in 1992, and $15,141 in 1994.
Prevalence: Prevalence is the number of cases of a disease, number of infected people, or number of people with a given attribute present during a particular interval of time. It is often expressed as a rate or percentage (for example, the prevalence of arthritis per 100 people during a year).
Psychiatric disorder: In the National Comorbidity Survey, respondents were interviewed about symptoms, using a structured diagnostic interview. Respondents whose symptoms met the criteria for a mental disorder as defined in the American Psychiatric Association's Diagnostic and Statistical Manual, Revised Third Edition (DSM-III-R) were classified as having a psychiatric disorder.
Rehabilitation Services Adminstration Program Data: See Appendix for description of data source.
Restricted-activity days: From the NHIS, a day when a person cuts down on his or her activities for more than half a day because of illness or injury. Include bed-disability, work-loss and school-loss days.
Rochester Epidemiology Project: See Appendix for description of data source.
SIPP: See Survey of Income and Program Participation in the Appendix for survey description.
School-loss days: From the NHIS, a day when a child loses more than half a school day because of illness or injury. School-loss days are computed for children 5-17 years of age.
Severe activity limitation: In the NHIS, a person who is "unable to carry on" his or her major activity is said to have a severe activity limitation.
Severe disability: Severe disability is defined by the SIPP as follows: People 15 and over were identified as having a severe disability if they
Serious mental illness (SMI): In the 1989 Mental Health Supplement to the National Health Interview Survey (NHIS-MH), serious mental illness was defined as having one or more psychiatric disorders in the past year that interfered seriously with one or more aspects of daily life. Household respondents were asked whether anyone in the household had one of a number of psychiatric disabilities, which were listed by name. This type of question differs from a survey like the Epidemiological Catchment Area (ECA) Survey and the National Comorbidity Survey, in which clinical interviews about symptoms were conducted to determine prevalence of mental disorders.
Severe mental disorder: In the Epidemiological Catchment Area (ECA) studies, subjects were interviewed using the Diagnostic Interview Survey and classified as having a severe mental disorder if their symptoms met the criteria for a particular set of Diagnostic and Statistical Manual (DSMIII) mental disorders and markedly interfered with social, occupational, and or school functioning. The diagnoses that are considered severe include schizophrenia and related disorders, manic-depressive (bipolar) disorder, autism and related disorders, and severe forms of major depression, panic disorder and obsessive compulsive disorder.
Severe work disability: The Current Population Survey (CPS) classified people as having a severe work disability if they:
(See also work disability.)
Special education: Special education refers to free and appropriate public education and related services provided for children and youth with disabilities from birth through age 21. Funding is provided via federal legislation IDEA, part B and, through 1995, by Chapter 1 of ESEA (SOP). (See also IDEA and ESEA.)
Social Security benefits: Social security benefits for individuals with disabilities include: (1) Social Security Disability Insurance (SSDI) which is a part of the Old Age, Survivors and Disability Insurance (OASDI) and (2) Supplemental Security Income (SSI). Individuals may receive benefits from either or both programs, depending on their work history, age, and financial resources. See individual listings under these terms for more information about each program.
Social Security Disability Insurance (SSDI): A federal program in the Social Security Administration providing monthly benefits to disabled workers and their dependents. A person builds protection through employment covered under Social Security (compulsory tax on earnings). The disability definition is an inability to engage in substantial gainful activity because of any medically determinable permanent physical or mental impairment. Later amendments made the disability length of time necessary for eligibility to be at least five months.
Social Security Program Data: See Appendix for description of data source.
Supplemental Security Income (SSI): The federally-administered Supplemental Security Income program provides income support to people 65 and over, blind or disabled adults and blind or disabled children who have little or no income or other financial resources. In order to be considered disabled for SSI, an adult must be unable to engage in any substantial gainful activity by reason of a medically determinable physical or mental impairment that is expected to result in death or last for a continuous period of at least 12 months. Blindness is defined as 20/200 or less vision in the better eye with the use of correcting lenses, or with tunnel vision of 20 degrees or less. Children who have a physical or mental impairment whi
U.S. Department of Education, Office of Special Education, Data Analysis System: See Appendix for description of data source.
Vocational Rehabilitation: This term refers to programs conducted by state Vocational Rehabilitation agencies operating under the Rehabilitation Act of 1973. Vocational Rehabilitation programs provide or arrange for a wide array of training, educational, medical, and other services individualized to the needs of people with disabilities. The services are intended to help people with disabilities acquire, reacquire, and maintain gainful employment. Most of the funding is provided by the federal government.
With employment outcome: The successful placement of a Vocational Rehabilitation client into competitive, sheltered, or self-employment for a minimum of 60 days after the completion of all necessary rehabilitation services. This category, "with employment outcome," was formerly called "rehabilitated."
Work disability: People were classified as having a work disability by the Current Population Survey (CPS) if they met any of the following criteria:
(See also Severe work disability.)
On the NHIS-D, work disability is defined as a limitation in or inability to work as a result of a physical, mental or emotional health condition.
Work limitation: In the NHIS, this category includes respondents with a chronic health condition that prevents the performance of work at all, allows only certain types of work to be performed or prevents regular working.
Work-loss days: From the NHIS, a day during which a person lost more than half a workday because of illness or injury. Work-loss days are computed for people 18 years and over, in the currently employed population (defined as those who were working or had a job or business from which they were not on layoff during the 2-week period preceding the week of interview).