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. 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.

Please refer to Section 5.3 of the CLSA Protocol, available under the Researchers section of our website.

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

Periods of data collection for Follow-Up 1 (FUP1) assessments were as follows:

FUP1 Tracking: 2014-05 to 2018-12

FUP1 Comprehensive: 2015-07 to 2018-12

No, it is not within the purview of the CLSA to advise approved users on statistical analyses for approved projects. Data Support Documentation is available under the Researchers tab of our website, including a detailed document on the use of Sampling Weights. For further help, please consult with a statistician.

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

CLSA is working centrally on strategies to link individual level CLSA data with data from health administrative databases across Canada. In 2021, the Health Data Research Network Canada (HDRN Canada) and the Canadian Longitudinal Study on Aging (CLSA) announced a new partnership to enable linkage of the CLSA cohort data with data held at provincial data centres. Please continue to monitor the website for updates.

Linking of the CLSA data to third party data holdings by an approved user is prohibited. Any proposals for linkage must be approved by the CLSA Scientific Management Team, and executed internally by the CLSA. Six-digit postal codes or HIN data are never released to users.

No, CLSA data are only available through a direct application to the CLSA. For more information on how to apply, please consult the Data Access Application Process section of our website.

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:

1)    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.

2)    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 dataset, 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.

Within the CLSA dataset, derived variables (DVs) are variables that are created from other variables. DVs are derived by re-grouping or re-classifying the original variables, to glean information otherwise not available. Some DVs are based on published measures or scales. You will find documentation related to DVs on our Data Support Documentation page, under the Researchers tab of our website.

Participant death is currently captured in three ways: 1) from the next of kin contacting the CLSA directly, 2) through the ‘maintaining contact’ telephone calls that occur between main waves of data collection, or 3) from linkage to provincial vital statistics. Mortality data including cause of death are not yet available, however, vital statistics are released along with the Follow-up 1 dataset that provide information on the vital status of participants up to July 2019.

The CLSA takes great care to check the accuracy and completeness of the data prior to release. However, because of the size of the dataset and the large number of variables, we cannot guarantee the accuracy, completeness, or fitness for any particular purpose of the data. It is the responsibility of each data user to verify their dataset, the accompanying data dictionaries and the Data Support Documentation available on our website. If you think your data are incomplete or if you identify errors while conducting your analyses, please contact us at access@clsa-elcv.ca.

The CLSA updates its datasets on a regular basis with additional data, corrections and other updates. Such changes are always indicated by the version number of a dataset. When an update is ready, we send a Data Release Update email to all approved Primary Applicants, explaining the change(s). You will be able to request the updated dataset if you are approved for those data and you decide that the updates are relevant to your project.