Data Dictionary: ACS 2005 -- 2007 (3-Year Estimates)
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Data Source: U.S. Census Bureau
Table: B99184. Imputation Of Mental Disability For The Civilian Noninstitutionalized Population 5 Years And Over [3]
Universe: Universe: Civilian noninstitutionalized population 5 years and over
Table Details
B99184. Imputation Of Mental Disability For The Civilian Noninstitutionalized Population 5 Years And Over
Universe: Universe: Civilian noninstitutionalized population 5 years and over
Variable Label
B99184001
B99184002
B99184003
Relevant Documentation:
Excerpt from: Social Explorer; U.S. Census Bureau; 2005-2007 American Community Survey 3-Year Summary File: Technical Documentation.
 
Imputation Rates
Missing data for a particular question or item is called item nonresponse. It occurs when a respondent fails to provide an answer to a required item. The ACS also considers invalid answers as item nonresponse. The Census Bureau uses imputation methods that either use rules to determine acceptable answers or use answers from similar housing units or people who provided the item information. One type of imputation, allocation, involves using statistical procedures, such as within-household or nearest neighbor matrices populated by donors, to impute for missing values.
Overall Person Characteristic Imputation Rate
This rate is calculated by adding together the weighted number of allocated items across a set of person characteristics, and dividing by the total weighted number of responses across the same set of characteristics.
Overall Housing Characteristic Imputation Rate
This rate is calculated by adding together the weighted number of allocated items across a set of household and housing unit characteristics, and dividing by the total weighted number of responses across the same set of characteristics. These rates give an overall picture of the rate of item nonresponse for a geographic area.

Excerpt from: Social Explorer; U.S. Census Bureau; 2005-2007 American Community Survey 3-Year Summary File: Technical Documentation.
 
Disability Status
Using models of disability from the Institute of Medicine and the International Classification of Functioning, disability is defined as the restriction in participation that results from a lack of fit between the individual's functional limitations and the characteristics of the physical and social environment. So while the disability is not seen as intrinsic to the individual, the way to capture it in a survey is to measure components that make up the process. The American Community Survey identifies serious difficulty in four basic areas of functioning: vision, hearing, ambulation, and cognition. Described below, the ACS asks respondents about serious difficulty and the resulting data can be used individually or combined. The ACS also includes two questions to identify people with difficulties that might impact their ability to live independently. In the 2007 American Community Survey, there are three disability questions, two with subparts totaling six questions in all, as described below.
Limitation of the Data
Beginning in 2006, the population in group quarters (GQ) is included in the ACS. The universe for most disability data tabulations is the civilian noninstitutionalized population. Some types of GQ populations have disability distributions that are different from the household population. The inclusion of the noninstitutionalized GQ population could therefore have a noticeable impact on the disability distribution. This is particularly true for areas with a substantial noninstitutionalized GQ population. For example, the number of people with a disability may increase in areas having a substantial group home population. In areas having a substantial college dormitory population, the percentage of people with a disability may decrease because the base of the percentage, which now includes the population in college dormitories, is larger.
Sensory and Physical Limitations
The data on sensory and physical limitations were derived from answers to Questions 15a and 15b, which were asked of people 5 years old and over. Questions 15a and 15b asked respondents if they had any of the following two long-lasting conditions: "Blindness, deafness, severe vision or hearing impairment," or "A condition that substantially limits one or more basic physical activities such as walking, climbing stairs, reaching, lifting, or carrying." Respondents were instructed to mark "yes" or "no" for each long-lasting condition. Question 15a is labeled as "Sensory disability" and Question 15b as "Physical disability" for some of the disability data products such as the ACS Detailed Tables.
Question/Concept History
For the 1996-1998 American Community Survey, the question, which was asked of persons 5 years old and over, instructed the respondents to mark each appropriate box if they had difficulty with any of the following three specific functions: "Difficulty seeing (even with glasses)," "Difficulty hearing (even with a hearing aid)," or "Difficulty walking." The respondents could mark as many as three boxes depending on their functional limitation status. If the respondents did not have difficulty with any of the three specific functions, the question instructed them to mark the box labeled "None of the above." The sensory and physical disability data obtained from the 1996-1998 American Community Survey are not comparable to data collected from the 1999-2007 American Community Surveys.
Limitations in Cognitive Functioning ("Mental Disability")
The data on cognitive functioning were derived from answers to Question 16a, which was asked of people 5 years old and over. The question asked respondents if they had a physical, mental, or emotional condition lasting 6 months or more that made it difficult "learning, remembering, or concentrating." Respondents were instructed to mark "yes" or "no." Question 16a is labeled as "Mental Disability" for some disability data products such as the ACS Detailed Tables.
Question/Concept History
No comparable data on cognitive functioning were obtained in the 1996-1998 American Community Survey. This question was introduced in the 1999 American Community Survey.
Self-Care Limitations
The data on self-care limitations were derived from answers to Question 16b, which was asked of people 5 years and over. The question asked respondents if they had a physical, mental, or emotional condition lasting 6 months or more that made it difficult "dressing, bathing, or getting around inside the home." Respondents were instructed to mark "yes" or "no." Question 16b is labeled as "Self-Care Disability" for some disability data products such as the ACS Detailed Tables.
Question/Concept History
No comparable data on self-care limitations were obtained in the 1996-1998 American Community Survey. This question was introduced in the 1999 American Community Survey.
Going-Outside-Home Limitations
The data on mobility limitations were derived from answers to Question 17a. Although Question 17a was asked of people 15 years and over, the data products only report this type of disability for people 16 years and over. The question asked respondents if they had a physical, mental, or emotional condition lasting 6 months or more that made it difficult "going outside the home alone to shop or visit a doctors office." Respondents were instructed to mark "yes" or "no." Question 17a is labeled as "Go-outside-home Disability" for some disability products such as the ACS Detailed Tables.
Limitation of the Data
The Census Bureau does not recommend trend analysis using the 2003-2007 data with years prior to 2003 due to the 2003 questionnaire change. For more information regarding the 2003 questionnaire change, view "Disability Data from the American Community Survey: A Brief Examination of the Effects of a Question Redesign in 2003" (http://www.census.gov/hhes/www/disability/ACS_disability.pdf ).
Question/Concept History
For the 1996-1998 American Community Survey, the data on going-outside-home limitations were derived from answers to Question 16a, which was asked of persons 16 years old and over. The question was slightly different from the 1999-2002 question and asked the respondents if they had a long-lasting physical or mental condition that made it difficult to "go outside the home alone to shop or visit a doctor's office." In the 1999-2002 American Community Survey, the going-outside-home question was part of Question 16. The 2003 questionnaire moved go-outside-home limitations to Question 17a and introduced a new skip instruction between Questions 16 and 17.
Employment Limitations
The data on employment limitations were derived from answers to Question 17b. Although it was asked of people 15 years and over, the data products only report this type of disability for people aged 16 to 64. The question asked the respondents if they had a physical, mental, or emotional condition lasting 6 months or more that made it difficult "working at a job or business." Respondents were instructed to mark "yes" or "no." Question 17b is labeled as "Employment Disability" for some disability data products such as the ACS Detailed Tables.
Question/Concept History
For the 1996-1998 American Community Survey, the data on employment limitations were derived from answers to Question 16b, which was asked of persons 16 years old and over. The question was slightly different from the 1999-2003 question and asked the respondents if they had a long-lasting physical or mental condition that "prevents this person from working at a job or business." In the 1999-2002 American Community Survey, the employment limitations question was part of Question 16. The 2003 questionnaire moved the employment limitations to Question 17b and introduced a new skip instruction between Questions 16 and 17.
Limitation of the Data
The Census Bureau does not recommend trend analysis using the 2003-2007 data with years prior to 2003 due to the 2003 questionnaire change. For more information regarding the 2003 questionnaire change, view "Disability Data from the American Community Survey: A Brief Examination of the Effects of a Question Redesign in 2003" (http://www.census.gov/hhes/www/disability/ACS_disability.pdf ).

Disability Status
The Census Bureau uses the six disability questions above to determine an individuals disability status in some of its data products such as in the ACS Detailed Tables and the Disability Profile. People aged 16 to 64 were classified as having a disability if they reported at least one of the above six limitations. People aged 5 to 15 were classified as having a disability if they reported any one of the four limitations: sensory disability, physical disability, mental disability, or self-care disability. People 65 and over were classified as having a disability if they reported any one of the five limitations: sensory disability, physical disability, mental disability, self-care disability, or going-outside-home disability.
Limitation of the Data
Since two of the six questions used to determine disability status are no longer comparable with those of the prior years, the Census Bureau does not recommend trend analysis using the 2003-2007 data with years prior to 2003. For more information regarding the 2003 questionnaire change, view "Disability Data from the American Community Survey: A Brief Examination of the Effects of a Question Redesign in 2003" (http://www.census.gov/hhes/www/disability/ACS_disability.pdf).
Excerpt from: Social Explorer; U.S. Census Bureau; 2005-2007 American Community Survey 3-Year Summary File: Technical Documentation.
 
Age
The data on age were derived from answers to Question 2. The age classification is based on the age of the person in complete years at the time of interview. Both age and date of birth are used in combination to calculate the most accurate age at the time of the interview. Inconsistently reported and missing values are assigned or imputed based on the values of other variables for that person, from other people in the household, or from people in other households ("hot deck" imputation). Data on age are used to determine the applicability of other questions for a particular individual and to classify other characteristics in tabulations. Age data are needed to interpret most social and economic characteristics used to plan and analyze programs and policies. Therefore, age data are tabulated by many different age groupings, such as 5-year age groups.
Median Age
The median age is the age that divides the population into two equal-size groups. Half of the population is older than the median age and half is younger. Median age is based on a standard distribution of the population by single years of age and is shown to the nearest tenth of a year. (See the sections on "Standard Distributions" and "Medians" under "Derived Measures.")
Age Dependency Ratio
The age dependency ratio is derived by dividing the combined under-18 and 65-and-over populations by the 18-to-64 population and multiplying by 100.
Old-Age Dependency Ratio
The old-age dependency ratio is derived by dividing the population 65 years and over by the 18-to-64 population and multiplying by 100.
Child Dependency Ratio
The child dependency ratio is derived by dividing the population under 18 years by the 18-to-64 population, and multiplying by 100.
Limitation of the Data
Caution should be taken when comparing population in age groups across time. The entire population continually ages into older age groups over time and babies fill in the youngest age group. Therefore, the population of a certain age is made up of a completely different group of people in 2000 and 2007. Since populations occasionally experience booms/increases and busts/decreases in births, deaths, or migration (for example, the postwar Baby Boom from 1946-1964), one should not necessarily expect that the population in an age group in Census 2000 should be similar in size or proportion to the population in the same age group in the 2007 ACS. For example, Baby Boomers were age 36 to 54 in Census 2000 while they were age 44 to 62 in the 2007 ACS. Therefore, the age group 55 to 59 would show a considerable increase in population when comparing Census 2000 data with the 2007 ACS data.
Beginning in 2006, the population in group quarters (GQ) is included in the ACS. Some types of GQ populations have age distributions that are very different from the household population. The inclusion of the GQ population could therefore have a noticeable impact on the age distribution. This is particularly true for areas with a substantial GQ population.
Question/Concept History
The 1996-2002 American Community Survey question asked for month, day, and year of birth before age. Since 2003, the American Community Survey question asked for age, followed by month, day, and year of birth. In 2007, an additional instruction was provided with the age and date of birth question on the American Community Survey questionnaire to report babies as age 0 when the child was less than 1 year old. The addition of this instruction occurred after 2005 National Census Test results indicated increased accuracy of age reporting for babies less than one year old.