Canadian Alcohol and Drugs Survey (CADS)

Detailed information for 2019




Every 2 years

Record number:


The main objective of this survey is to collect information on Canadians' use of alcohol and drugs. Health Canada and other organizations will use the information to monitor changes in alcohol and drug use.

Data release - December 20, 2021


The major objectives of the Canadian Alcohol and Drugs Survey are to: measure frequency of alcohol use, measure frequency of cannabis use, measure frequency of use of other drugs and measure potential harmful effects of alcohol, cannabis and other drugs.

Up until 2017, Statistics Canada conducted the Canadian Tobacco, Alcohol and Drugs Survey (CTADS), which collected data on tobacco as well as alcohol and drugs. Starting with the collection of the 2019 Canadian Alcohol and Drugs Survey (CADS), content on alcohol and drugs has been collected on its own. The Canadian Tobacco and Nicotine Survey (CTNS) has been conducted as a separate survey to collect data on tobacco and nicotine.

Reference period: Varies (past 7 days, past 30 days, past 3 months, past 12 months and during lifetime).

Collection period: June to December of the reference year


  • Health
  • Lifestyle and social conditions

Data sources and methodology

Target population

The target population for the Canadian Alcohol and Drugs Survey is all persons 15 years of age and older living in Canada with the following exceptions:
- Residents of the Yukon, Northwest Territories and Nunavut;
- Institutionalized population;
- Residents on First Nations reserves

Instrument design

The CADS 2019 questionnaire was developed in coordination with the survey sponsor, Health Canada.

The questionnaire for CADS 2019 contains some of the same questions as the previous CTADS (2013, 2015 and 2017) questionnaires and previous iterations of the Canadian Tobacco Use Monitoring Survey CTUMS. However, many new questions have been introduced. In particular, more information was collected on alcohol consumption, and on a wider variety of drugs and the effects of their use.

During March and July 2018, qualitative testing took place to test new and revised questionnaire content. Close to 50 cognitive interviews were conducted face-to-face with participants to determine if the content was relevant and well understood. After each round of testing, changes were made to the wording and flows based on observations of the interviews and comments received by participants.


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

The frame is the Dwelling Universe File (DUF) produced by Statistic Canada. Dwellings in the Yukon, the Northwest Territories and Nunavut were excluded, as well as dwellings on Native reserves.

Sampling unit
The CADS sample has a two-stage design: the sampling unit for the first stage is the dwelling, and the sampling unit for the second stage is the person.

Stratification method
The CADS frame was stratified by province and a simple random sample of dwellings was selected independently within each province.

Sampling and sub-sampling
Sufficient sample was allocated to each of the provinces so that the survey could produce provincial and national level estimates by age groups. An initial sample of 22,116 dwellings was selected.

Data sources

Data collection for this reference period: 2019-06-10 to 2019-12-31

Responding to this survey is voluntary.

Data are collected directly from survey respondents.

Selected households receive an invitation letter in the mail. The letter explains who, from the household, was selected to participate in the survey using the age selection method. The access code in the letters gave the respondent access to the electronic questionnaire. The electronic questionnaire was offered in the two official languages: French and English. The median time required to complete the survey was 17 minutes. The majority of respondents have taken between 13 and 23 minutes to complete the questionnaire. A non-responding household could have received up to four mail reminders before they were contacted by a Statistics Canada interviewer to complete the questionnaire over the phone.

View the Questionnaire(s) and reporting guide(s) .

Error detection

The purpose of processing survey data is to put the collected data into a form that is appropriate for analysis and tabulation.

For the CADS, collection was performed using an electronic questionnaire and, when required, by a Computer Assisted Telephone Interview (CATI). The electronic format of the questionnaire allows for certain edits to be built into the application. For example, Validity Edits, which ensure that the response falls within the allowed range.

After collection, the raw data files were appended together and put through a series of standard processing steps designed to clean the data and help ensure its consistency, thereby increasing its usefulness and its quality. Edits were done on the data both at the micro and macro level.

Another set of data processing procedures included the verification of the response paths and question flows built into the questionnaire. Questions that did not apply to the respondent's situation based on the answers to previous questions were assigned a "valid skip" value. Non-responses were set to a value of 'Not Stated'. These are questions that were applicable to the respondent but were not answered.

In addition, various types of editing were done to detect missing or inconsistent information. For example, edits were performed to check the logical relationship between responses.

New variables (derived variables) were derived using collected variables. A derived variable may be based on one variable by re-grouping or collapsing the categories or based on several variables, by combining them together to define a new concept.


No imputation methods were employed for the CADS 2019.


For the microdata file, weights were placed on each record to represent the number of sampled persons that the record represents in the population.
The weighting for the Canadian Alcohol and Drug Survey file consisted of several steps, beginning with household weight:

1) calculation of initial weight: each household selected represents multiple other households within the strata;
2) dropping out-of-scope records;
3) adjustments for non-responding households (key questions missing);
4) adjustments to make the household estimates consistent with known province totals obtained from population projections.

Person weight calculation starts with the household weights in step 4:

5) calculation of weight for the selection of the person in the household, based on age selection
6) adjustments to make the population estimates consistent with known province, age groups, sex and census metropolitan area totals from the population projections.

To estimate variances, bootstrap weights were also created and made available in another file.

Quality evaluation

While rigorous quality assurance mechanisms are applied across all steps of the statistical process, validation and scrutiny of the data by statisticians are the ultimate quality check prior to dissemination. Many validation measures were implemented. They include:

a. Analysis of changes over time
b. Verification of estimates through cross-tabulations
c. Confrontation with other similar sources of data
d. Coherence analysis based on Quality Indicators

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 publication or disclosure of any information deemed confidential. If necessary, data are suppressed to prevent direct or residual disclosure of identifiable data.

A Public Use Microdata File (PUMF) is available for the CADS. It should be noted that the PUMF differs from the survey "master" file held by Statistics Canada. Differences between the two files are usually the result of actions taken to protect the anonymity of individual survey respondents on the PUMF. The most common actions are the suppression of file variables, grouping values into wider categories, and coding specific values into the "not stated" category. Users requiring access to information excluded from the PUMF may purchase custom tabulations. Estimates generated will be released to the user, subject to meeting the guidelines for analysis and release.

Revisions and seasonal adjustment

This methodology type does not apply to this statistical program.

Data accuracy

Non-sampling errors can be defined as errors arising during the course of virtually all survey activities, apart from sampling. They are present in both sample surveys and censuses (unlike sampling errors, which are only present in sample surveys). Non-sampling errors arise primarily from the following sources: non-response, coverage, measurement and processing.

The CADS 2019 response rate is higher than it was for CTADS 2017. It is therefore possible than the non-reponse bias will be less important than in 2017.

For CADS 2019, the overall response rate was 50.7%.

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