Researchers

In general, variables in the CLSA dataset reflect the interview process. In some cases, follow-up questions were only asked if specific answers were given to preceding questions.

Blank values in the Baseline data can represent multiple types of missing data, including:

Valid skip patterns. For example, number of daughters and sons are only asked if the participant answered that they have at least one child. In the CLSA dataset, participants with no children will have blank values for both.

Missing data due to non-completion. There are some participants who skipped entire sections of baseline interview, and therefore have blanks for all the questions in those sections. Indicator variables such as ADM_COMPLETE_MCQ are provided in the documentation accompanying data release and should be consulted when there are large number of missing data to determine if it is due to a participant not completing a section.

In the Follow-up 1 and Follow-up 2 datasets, missing data have been assigned various codes according to the reason the data are missing. Details of the different types of missing data are provided in the data dictionaries accompanying datasets.

No, the CLSA does not have bootstrap weights for the dataset, and we are not planning to produce bootstrap weights in the near future.

At Baseline, 21,241 participants were enrolled in the Tracking cohort and 30,097 participants in the Comprehensive cohort for a total of 51,338 CLSA participants.

The 30-minute Maintaining Contact Questionnaire (MCQ) interviews with additional health-related questions were completed approximately 18 months after the initial Baseline data collection. A total of 19,052 Tracking participants and 28,789 Comprehensive participants completed the MCQ. The indicator variable ADM_COMPLETE_MCQ is included in the dataset to indicate those participants who completed the MCQ.

From the Variables Search, accessed through the DataPreview Portal, full-text searches can be carried out on either the variable Name or Label. The variables can also be filtered by classification through the clickable boxes on the left. To see all of the questionnaires used by the CLSA, you can visit Researcher Resources.

To obtain all the variables contained in a questionnaire, type the two or three letter prefix (e.g. SDC for Socio-demographic Variables) into the full-text search box in the Variables listing, under “Variable properties > Name”. You can also use more general terms such as ‘food’, ‘work’, etc. (under “Variable properties > Label”) to find variables related to those terms, however, search terms are not exhaustive. For more information on the variables included in a questionnaire, please visit  Researcher Resources.

Multiple-choice questions are represented by either a single variable or multiple variables, depending on what the question allows:

– A question allowing only one response is represented by a single variable that can take on multiple values. Open-text responses are permitted in many questions; common and distinct responses are recoded to create new categories within the variable itself.

– For a question allowing multiple responses, each possible response category is assigned its own binary variable. Open-text responses are also permitted in many of these questions; common and distinct options are also recoded to create additional variables within the question scope. The number of variables corresponding to that question matches the number of response options.

In the variable view, clicking on the name of each variable reveals information that is more detailed. For example, under Categories, the variable information page will include the following information:

Name: the value entered for a response in the questionnaire;

Label: the response (or response category) corresponding to each value (Name);

Missing: values corresponding to a question not answered, (don’t know or not applicable, refused).

Clicking on the variable name, in the variable view reveals more detailed information about that variable. (This function is not available for all study variables). This information includes the question pertinent to the variable, the variable label, a list of the response option categories and some automatically generated summary statistics. In some instances, additional notes on skip patterns or references are included as well.

Please refer to Section 5.3 of the CLSA Protocol, available under Protocols within Researcher Resources.

Periods of data collection for the Baseline assessments were as follows:

Baseline Tracking: 2011-09 to 2014-05
Baseline Comprehensive: 2011-12 to 2015-07
Maintaining Contact Questionnaire (MCQ) Tracking: 2013-09 to 2016-02
Maintaining Contact Questionnaire (MCQ) Comprehensive: 2014-05 to 2016-01

All questionnaires and modules made available on our website must be referenced as appropriate. Please refer to Appendix 2: Conditions of Use Associated with Scales, Tests, and Measures in the CLSA in the Publication and Promotion Policy for CLSA Data Users for the sources and associated Conditions of Use of the questionnaires used in the CLSA.

If referencing CLSA modules and questionnaires not covered in the Supplementary Conditions of Use, the format of the citation should be as follows:

Canadian Longitudinal Study on Aging, [Name of module or questionnaire] [(wave of data collection)]; available at: [Website]; consulted on: [date].

If a questionnaire has been modified by the CLSA, the format of the citation should be as follows:

Canadian Longitudinal Study on Aging, [Name of module or questionnaire] [(wave of data collection)] adapted from [Source, ex. Survey by government agency, research study]; available at: [Website]; consulted on: [date].

For example, the Social Networking (SN) questionnaire was modified by the CLSA from the General Social Survey by Statistics Canada:

Canadian Longitudinal Study on Aging, Social Networks Questionnaire (Baseline) adapted from the General Social Survey, Statistics Canada; available at: https://www150.statcan.gc.ca/n1/en/catalogue/89F0115X; consulted on: July 23, 2018.

As a publicly funded research platform, the CLSA encourages the dissemination of research findings from approved projects. The CLSA expects users to publish their findings in peer-reviewed journals. Multiple publications may be prepared based on a single approved project as long as the publications are directly linked to the objectives of the approved project.