Health and Activity Limitation Survey: Household Component (HALS)

Detailed information for 1986

Statistics Canada is conducting a survey on Canadians (adults and children), whose day-to-day activities may be limited because of a condition or health problem. Survey results will help to identify difficulties and barriers these Canadians may face.

Data release - May 1989

• Description
• Data sources and methodology

Description

The Health and Activity Limitation Survey: Household Component (HALS) is used to identify the numbers and distribution of disabled persons in Canada. The type of data gathered include the nature and severity of disability and the barriers which disabled person encounter in all aspects of their daily activities.

Subjects

• Disability
• Equity and inclusion
• Health
• Society and community

Data sources and methodology

Target population

The target population of HALS: Household Component consisted of all persons with a physical or psychological disability who were living in Canada at the time of the Census, including residents of the Yukon and the Northwest Territories. Indian reserves were covered by the Aboriginal Peoples Survey also conducted by Statistics Canada.

Sampling

This is a sample survey with a cross-sectional design.

Question 20 on the Census 2B questionnaire was included in the 1986 Census of Population to identify the population that experienced some activity limitation or that had a long term disability or handicap. Personal interviews were conducted with a sample of selected individuals age 15 and older who answered 'YES' to at least one part of Question 20. A proxy interview was conducted for all selected individuals aged 14 and younger. A sample of individuals who answered 'NO' to all parts of Question 20 was also selected. It is anticipated that a portion of these individuals will be converted to the 'YES' sample. Four questionnaires were used: adults, adults - northern areas, children under 15 years and children under 15 years - northern areas.

The household survey took place in two stages. The first stage consisted of Question 20 about activity limitations and disabilities included on the Census long form, which was asked of every fifth household. The second stage was the completion of the HALS household questionnaire.

The purpose of this question was to identify, prior to the survey, a large part of the potential disabled population, in order to focus survey resources on the target group as much as possible.

Identification of eligible respondents for the household component of HALS was an integral part of the 1986 Census field operation. As part of their responsibilities, 23,530 Census Representatives were trained to review the completed Census questionnaires and to create a list of individuals who had responded positively to the disability question on the Census form. Two major strata were formed--Indian reserves and all other areas. All Indian reserves were included in the survey and a sample of the remaining areas were selected.

Data sources

Responding to this survey is voluntary.

Data are collected directly from survey respondents.

Data collection for the household survey took place in the summer of 1986 immediately following the completion of the field work for the 1986 Census. Twelve hundred Census representatives received additional training on the survey content and procedures, and conducted the interviews. For the part of the sample made up of persons who had indicated limitations in response to Question 20 on the Census form, in most cases the data were collected by means of personal interviews. For the "No" sample, telephone interviews were usually conducted.

For children, the interview was to be done with a parent or other adult. For adults, the interview was to be done with the selected respondent. However, in some situations, the interview was conducted with another member of the household; for example, when the respondent's physical or psychological state prevented him or her from participating in the survey. Approximately 12% of the interviews with adults were done this way.

Error detection

All HALS data base records were subjected to complex computer editing in which the validity and consistency of responses were checked. Missing or erroneous data were identified as "unknown", or in some cases, were imputed using other information contained in the same questionnaire.

Data capture for the household and institutions components of the survey were done in Statistics Canada regional offices. The data were then transmitted to Statistics Canada headquarters in Ottawa for subsequent processing. When capture was completed, the survey questionnaire was shipped to Ottawa.

Estimation

Statistics from the Health and Activity Limitation Survey (HALS) data base are estimates based on a sample survey of a portion of the Canadian population (approximately 1 out of every 25 persons in the 'yes' sample and 1 out of every 300 persons in the 'no' sample). As a result, the statistics are subject to two types of error: sampling and non-sampling errors.

In a sample survey such as HALS, each respondent in the sample represents a subset of persons in the population being studied. Consequently, each data base record is assigned a weight corresponding to the number of persons represented. In addition, the weight is further modified to offset non-response and discrepancies between the population studied and the target population.

HALS records were weighted to represent the Canadian population excluding persons not eligible for the survey, which were those in penal institutions and correctional facilities, and on reserves not enumerated in the 1986 Census.

Sampling error is the difference between the estimate derived from a sample and the result that would have been obtained from a population census using the same data collection procedures. For a sample survey such as HALS, this error can be estimated from the survey data. The degree of error reflects the standard deviation of the estimate. When a sampling error is more than 25% of the estimate itself, it is considered to be too unreliable to be published. In such a case, the symbol '--' appears in statistical tables in place of the estimate. When the sampling error is between 16.5% and 25%, the corresponding estimate is accompanied by the symbol '*' in a table. Such estimates should be used with caution. Finally, all estimates with a sampling error of less than 16.5% can be used without restriction.

All other types of errors (observation, response, processing and non-response errors) are called non-sampling errors. Identifying and evaluating the importance of many of these errors can be difficult.

Observation errors arise when there is a difference between the target population and the sample population. Integrating HALS with the census of population has made it possible to greatly reduce this type of error. Only a certain portion of Indian reserves and collective dwellings were systematically ignored in the sampling process, but their importance is negligible compared to the total population. Consequently, observation errors should not have a significant influence on the HALS data.

All statistical surveys are susceptible to a certain percentage of non-response among the selected sample. A total non-response occurs when, for one reason or another, a selected respondent could not be interviewed. The non-response is said to be partial if only part of the questionnaire is complete. The impact of non-response errors on estimates depends on the level of non-response and particularly, on any differences between the characteristics of respondents and non-respondents. In principle, the more marked these differences, the greater the impact on the accuracy of the estimates.

With respect to HALS, the response rate (90%) compares favourably with the rate generally observed for this type of survey. In addition, various methods have been used to reduce the bias caused by any total non-responses, notably by adjusting the data to reflect the distribution of certain demographic characteristics obtained by the census. As well, response rates were higher for most specific questions. In tables, non-responses appear in the column labeled 'Unknown' or 'Not stated'.

Disclosure control

Statistics Canada is prohibited by law from releasing any information it collects that could identify any person, business, or organization, unless consent has been given by the respondent or as permitted by the Statistics Act. Various confidentiality rules are applied to all data that are released or published to prevent the publication or disclosure of any information deemed confidential. If necessary, data are suppressed to prevent direct or residual disclosure of identifiable data.

In order to prevent any data disclosure, confidentiality analysis is done using the Statistics Canada Generalized Disclosure Control System (G-Confid). G-Confid is used for primary suppression (direct disclosure) as well as for secondary suppression (residual disclosure). Direct disclosure occurs when the value in a tabulation cell is composed of or dominated by few enterprises while residual disclosure occurs when confidential information can be derived indirectly by piecing together information from different sources or data series.