Health and Activity Limitation Survey: Household Component (HALS)
Detailed information for 1991
Status:
Active
Frequency:
Every 5 years
Record number:
3251
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 - August 1994
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.
The household survey was carried out in two stages. The first involved adding two questions to the 1991 long Census form and the second involved conducting the actual survey for adults and children.
The two Census questions (#18 and #19, on activity limitation and long term disability respectively) were designed to identify prior to the actual survey , the target population. Once the target population was identified survey resources could then be concentrated on this group as opposed to the population at large. The questions were included on the 1991 long Census form, which was distributed to every fifth household.
Results of field tests conducted prior to the 1986 Census indicated that many persons with a disability did not answer "yes" to the questions on activity limitation. Although typically these persons were more active and had less serious disabilities than the others, they represented a particular segment of the population of persons with disabilities and therefore, still needed to be sampled to avoid significant biases in the estimates. Consequently it was decided to select and include in HALS a sample of individuals who responded "no" to the disability questions on the 1991 Census. This group of people became the "no" sample. The persons who answered positively constituted the "yes" sample.
All persons in the "no" sample were interviewed. If a positive response was obtained to having an activity limitation, then the questionnaire was completed, otherwise the interview ended. Since 5% of persons interviewed changed their "No" to a "Yes", 5,600 additional persons were added to the sample of persons with disabilities.
Data sources
Data collection for this reference period: August 1991 to October 1991
Responding to this survey is voluntary.
Data are collected directly from survey respondents.
Data collection for the Households Survey took place in the fall of 1991, immediately after the 1991 Census. For the "yes" sample, most of the interviews were conducted by telephone. In some special cases personal interviews were carried out. For the "no" sample, all interviews were done by telephone.
Children's interviews were conducted through a parent or other adult. However if the parent or guardian of an older child insisted that the child answer for him or herself, the interviewer was to comply.
Error detection
All records on the HALS database were put through a series of verification procedures to check the validity and consistency of responses. Missing, incomplete or inconsistent data were identified as "unknown", or in some cases, were estimated using other information contained in the same questionnaire.
Data capture for the households and institutional surveys were done in Statistics Canada regional offices. After data capture was completed, the data were transmitted and the questionnaires shipped to Statistics Canada Headquarters in Ottawa for processing and for further reference respectively.
Estimation
Statistics from the 1991 Health and Activity Limitation Survey (HALS ) database are estimates based on a sample survey of a portion of the Canadian population (approximately 1 out of 75 persons in the " yes" sample and 1 out of 200 persons in the "no" sample). As a result, the statistics are subject to two types of errors: sampling and non-sampling errors.
In a sample survey such as HALS, each respondent in the sample represents a sub-group of the population observed. Consequently, each database record is assigned a weight corresponding to the number of persons it represents. In addition the weight is further modified to offset non-responses and discrepancies between the population observed and the target population. The results of this survey are then multiplied by the numerical weight to provide an estimate of what the response would be for the entire population. HALS records were weighted to represent the Canadian population excluding persons not eligible for the survey.
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 is estimated from the survey data. The measurement of error used is the standard deviation of the estimate. When a sampling error is more than 33 1/3% 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 2/3% and 33 1/3%, 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 2/3% can be used without restriction.
All other types of errors (coverage, response, processing and non-response) are called non-sampling errors. It is generally difficult to identify and evaluate precisely some of these errors.
Coverage errors arise when there is a difference between the target population and the sample population. Integrating HALS with the census of population has greatly reduced this type of error. Only a certain portion of Indian reserves and collective dwellings were excluded from the sampling process, but because of their small numbers their effect on the total population is negligible. Consequently, coverage errors should not have a significant influence on the HALS data.
A response error occurs when the respondent misunderstands a question, and the interviewer records an incorrect answer.
Processing errors may occur at various stages including: coding, data capture and imputation.
All statistical surveys are susceptible to a certain percentage of non-response among the selected sample. Total non-response occurs when, for one reason or another, a selected respondent cannot be interviewed. Partial non-response occurs if only part of the questionnaire is completed. 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 of 87% 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 non-responses (e.g., adjusting the data to reflect the distribution of certain demographic characteristics obtained from the census).
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.
Documentation
- Health and Activity Limitation Survey - 1991 - Data Quality Statements
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