Canadian Tobacco, Alcohol and Drugs Survey (CTADS)

Detailed information for February to December 2013




Every 2 years

Record number:


The overall objective of the survey is to provide continual and reliable data on tobacco, alcohol and drug use and related issues, with the primary focus on 15 to 24 year olds.

Data release - February 3, 2015


As of 2013, new content, covering alcohol use as well as prescription and non-prescription drug use, was added to the Canadian Tobacco Use Monitoring Survey (CTUMS). Therefore; the survey is now entitled Canadian Tobacco, Alcohol and Drugs Survey (CTADS). Information about CTUMS is available through the "Other reference periods" sidebar on this Web page.

The overall objective of CTADS is to provide continual and reliable data on tobacco, alcohol and drug use and related issues, with the primary focus on 15 to 24 year olds.

The major objectives of the survey are to: measure the frequency of cigarette smoking, measure the amount smoked, gain insight into behaviors related to smoking, measure the prevalence and frequency of alcohol use, measure the prevalence of drug use and the extent of harm related to usage.

Reference period: February 1 to December 31

Collection period: Interviews are conducted every month from February to December.


  • Health
  • Lifestyle and social conditions

Data sources and methodology

Target population

All persons 15 years of age and over living in Canada with the following two exceptions:

1) residents of the Yukon, Northwest Territories and Nunavut, and
2) full-time residents of institutions.

Instrument design

The questionnaire design for this survey borrows heavily from the 1994 Survey on Smoking in Canada. Some questions have been added for consistency with international surveys which use the concept of smoking behaviour "in the last 30 days". In most cases questions added to the CTADS come from other Statistics Canada surveys. Interviewers are consulted about changes to the instrument.

All content related to alcohol and drugs comes from the Canadian Alcohol and Drug Use Monitoring Survey (CADUMS) that has been conducted by Health Canada since 2008.


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

The sample design is a special two-phase stratified random sample of telephone numbers. The two-phase design is used in order to increase the representation in the sample of individuals belonging to the 15 to 19 and 20 to 24 age groups. In the first phase, households are selected using Random Digit Dialing. In the second phase, one or two individuals (or none) are selected based upon household composition.

Data sources

Data collection for this reference period: 2013-02-01 to 2013-12-31

Responding to this survey is voluntary.

Data are collected directly from survey respondents.

Data were collected using computer-assisted telephone interviewing (CATI). A front-end module contains a set of standard response codes for dealing with all possible call outcomes, as well as the associated scripts to be read by the interviewers. A standard approach set up for introducing the agency, the name and purpose of the survey, the survey sponsors, how the survey results will be used, and the duration of the interview was used.

The CATI application ensured that only valid question responses were entered and that all the correct flows were followed. Edits were built into the application to check the consistency of responses, identify and correct outliers, and to control who gets asked specific questions. This meant that the data were already quite "clean" at the end of the collection process.

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

Error detection

The first type of error treated was errors in questionnaire flow, where questions which did not apply to the respondent (and should therefore not have been answered) were found to contain answers. In this case a computer edit automatically eliminated superfluous data by following the flow of the questionnaire implied by answers to previous, and in some cases, subsequent questions.

The second type of error treated involved a lack of information in questions which should have been answered. For this type of error a non-response or "not-stated" code was assigned to the item.


This methodology type does not apply to this statistical program.


The main output of the CTADS is two microdata files, one for the household level information and one for the person level information.

For the microdata file, statistical weights were placed on each record to represent the number of sampled persons that the record represents. One weight was calculated for each household and a separate weight was calculated and provided on a different file, for each person.

The weighting for the CTADS consists of several steps: calculation of a basic weight, followed by several adjustments such as non-response, non resolved telephone numbers and an adjustment for households with multiple telephone lines. Additional adjustments were made to account for the number of persons (0, 1 or 2) selected in the household and the over-sampling of the 15 to 24 age group. The last step of weighting consists of an adjustment to the person weights in order to make population estimates consistent with external population counts for persons 15 years and older (calibration). The following external control totals were used:

1) Monthly population totals for each province, and

2) Population totals by province, sex and the following age groups: 15 to 19, 20 to 24, 25 to 29, 30 to 34, 35 to 39, 40 to 44, 45 to 49, 50 to 54, 55 to 59, 60 to 64, 65 to 69, and 70 and over. These totals were averaged over the survey period.

The method called generalized regression (GREG) estimation was used to modify the weights to ensure that the survey estimates agreed with the external totals simultaneously along the two dimensions.

In order to supply coefficients of variation (CV) which would be applicable to a wide variety of categorical estimates produced from this microdata file and which could be readily accessed by the user, a set of Approximate Sampling Variability Tables has been produced. These CV tables allow the user to obtain an approximate coefficient of variation based on the size of the estimate calculated from the survey data.

The coefficients of variation in these tables are derived using the variance formula for simple random sampling and incorporating a factor which reflects the multi stage, clustered nature of the sample design. This factor, known as the design effect, was determined by first calculating design effects for a wide range of characteristics and then choosing from among these a conservative value to be used in the CV tables which would then apply to the entire set of characteristics.

The variance estimation method used until 2004 was Jackknife. Starting with Cycle 1 2004, it is mean Bootstrap.

Quality evaluation

Considerable time and effort was made to reduce non sampling errors in the survey. Quality assurance measures were implemented at each step of the data collection and processing cycle to monitor the quality of the data. These measures include extensive training of interviewers with respect to the survey procedures and computer-assisted telephone interviewing (CATI) application, observation of interviewers to detect problems of questionnaire design or misunderstanding of instructions and testing of the CATI application to ensure that range checks, edits and question flow were all programmed correctly.

Disclosure control

Statistics Canada is prohibited by law from releasing any information it collects which 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.

It should be noted that the "Public Use" microdata files differ in a number of important respects from the survey "master" files held by Statistics Canada. These differences are the result of actions taken to protect the anonymity of individual survey respondents. Confidentiality is ensured by suppressing and collapsing variables that may be used to identify individuals.

Revisions and seasonal adjustment

This methodology type does not apply to this statistical program.

Data accuracy

The household response rate for the CTADS, February to December 2013 Annual Summary was 77.1%. The person response rate was 81.8%.

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