National Apprenticeship Survey (NAS)

Detailed information for 2007





Record number:


The NAS collects information on the work and training experiences of apprentices before, during and after their involvement with their apprenticeship program.

Data release - June 9, 2008


The National Apprenticeship Survey (NAS) is Canada's most comprehensive pan-Canadian source of data on apprenticeship, collected from apprentices. It provides a standardized source of data across all provinces and territories.

The NAS collects information on the work and training experiences of apprentices before, during and after their involvement with their apprenticeship program.

The survey has three major objectives:

1. to better understand why a large percentage of registered apprentices do not complete the program;
2. to better understand to what extent program completion effects the labour market outcome of journeymen; and,
3. to identify why some apprentices take much longer to complete the program than expected.

The information from this survey will be used by many groups, including government departments (Federal, Provincial and Municipal), researchers from various universities and private organizations.


  • Education, training and learning
  • Job training and educational attainment
  • Labour
  • Outcomes of education

Data sources and methodology

Target population

The target population is the registered apprentices in the ten provinces, Yukon and Northwest Territories from the reference years of 2002, 2003 and 2004. Nunavut was excluded as they did not participate. This survey specifically targets the following three groups of apprentices: Completers, Discontinuers and Long-term continuers. For Completers and Discontinuers, apprentices had to be identified as such on the list of apprentices provided by each jurisdiction for the reference years 2002, 2003 and 2004. Long-term continuers were defined as all active apprentices (continuers) as of December 31, 2004 that registered as apprentices before the year 2000 (in the same trade as of the one in 2004). At the collection stage, a selected person from any of the three groups defined above was considered in scope for the survey if that person had some apprentice activities between 2000 and 2004.

Instrument design

Statistics Canada designed the NAS questionnaire in partnership with Human Resources and Social Development Canada (HRSDC) and the Canadian Council of Directors of Apprenticeship (CCDA). Various tools and methods were used to design the NAS questionnaire:
- Previous iteration of surveys on apprenticeship like the National Apprenticed Trades Survey (1994-1995);
- Panel groups of internal and external subject-matter experts
- Standard modules of questions from other STC surveys, like, for example, the use of some Labour Force Survey questions to collect data on labour force activities of the apprentices;
- Statistics Canada's Questionnaire Design Resource Centre (QDRC) to set-up testing of the questionnaire using focus groups and one-on-one interviews with apprentices in Halifax, Saskatoon, Toronto and Montreal;
- Revisions to the questionnaire were done after each set of testing and changes approved by HRSDC and the CCDA.


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

The survey frame represents all registered apprentices on the lists of apprentices provided by the provincial and territorial jurisdictions for the targeted reference years 2002, 2003 and 2004. Three variables on the frame were used for stratification: jurisdictions, apprentice status and main trade groups. There are 12 jurisdictions (10 provinces, Yukon and NWT), three apprentice status (completer, discontinuer and long-term continuer), and finally there are 7 main trade groups. The combination of these variables makes for a total of 231 strata.

To provide reliable estimates for each stratum, a national sample size of approximately 30,000 respondents was desired. A minimum sample was allocated to each stratum and the remaining sample was allocated proportionally to the number of apprentices in each stratum. In several strata, a census of apprentices was selected. Moreover, in small provinces and territories, it resulted in selecting a census of apprentices.

Within each stratum, a random sample of apprentices was selected.

Data sources

Data collection for this reference period: 2007-01-01 to 2007-04-30

Responding to this survey is voluntary.

Data are collected directly from survey respondents.

Data are collected using Computer assisted telephone interviewing (CATI). Interviews by proxy are not allowed.

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 graduate (and should therefore not have been answered) were found to contain answers. In this case an edit eliminated superfluous data by following the flow of the questionnaire implied by answers to previous 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.

For quantitative variables such as personal income, editing which includes outlier detection and imputation was performed. Potential outliers were identified and manual investigations were made on these cases to confirm their outlier status. Outliers were coded to "not stated", replaced by a more plausible value when a realistic value could be deduced from the other variables or imputed using a deterministic method.


For the personal income variables, nearest donor imputation was used, which involves copying information from another individual (i.e., a 'donor') with similar characteristics.


In order for estimates produced from survey data to be representative of the target population, and not just of the sample itself, users must incorporate the survey weights into their calculations. A survey weight is given to each person included in the final sample, that is, the sample of persons who responded to the survey questions. This weight corresponds to the number of persons represented by the respondent for the target population.

For weighting purpose, this survey can be seen as a two-phase survey. The first phase corresponds to the selection of the sample and the responding units correspond to the second phase sample. The first phase weight is the inverse of the probability of selection of the apprentice. This first phase weight is then multiplied by a second phase adjustment factor. For the purpose of the second phase adjustment, response homogeneous groups (RHG) are created based on the characteristics of the respondents and the non-respondents. The adjustment factor is simply the inverse of the observed weighted response rate in each RHG.

For variance estimation, the two-phase approach of the Generalized Estimation System (GES) was used.

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.

Revisions and seasonal adjustment

This methodology type does not apply to this statistical program.

Data accuracy

While considerable effort is made to ensure high standards throughout all stages of collection and processing, the resulting estimates are inevitably subject to a certain degree of error. These errors can be broken down into two major types: non-sampling and sampling. Frame imperfection and non-response are important sources of non-sampling error.

A large proportion of apprentices in the sample were found to be out-of-scope (not any apprentice activities during the target reference period) due to the frame imperfection. Overall, the out-of-scope rate was 25.9%. Provincial/territorial out-of-scope rates ranged from 10% to 40%. The out-of-scope rate was 7.9% for completers, 35.4% for long-term continuers and 39.3% for discontinuers.

The response rate for this survey was 62.3%. The response rate represents the number of respondents divided by the estimated number of in-scope apprentices in the entire sample. For the calculation of this response rate, the number of in-scope units from the nonrespondents had to be estimated using a logistic regression model. Provincial/territorial response rates ranged from 46.5% to 78.5%. The reponse rate was 69.3% for completers, 64.6% for long-term continuers and 51.9% for discontinuers.

The basis for measuring the potential size of sampling errors is the standard error of the estimates derived from survey results. Because of the large variety of estimates that can be produced from a survey, the standard error of an estimate is usually expressed relative to the estimate to which it pertains. This resulting measure, known as the coefficient of variation (CV) of an estimate, is obtained by dividing the standard error of the estimate by the estimate itself and is expressed as a percentage of the estimate.


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