Sampling and Weighting Technical Report, Census of Population, 2016
1. Census data collection

The purpose of data collection for the 2016 Census was to ensure that each of the 15.4 million dwellings in Canada was enumerated and that, for each occupied dwelling, the corresponding household completed a census questionnaire. The census enumerated the entire population of Canada, which consists of Canadian citizens (by birth and by naturalization), landed immigrants and non-permanent residents, as well as the family members living with them. Non-permanent residents are persons living in Canada who have a work or study permit or are claiming refugee status, as well as the family members living with them.

The census also enumerated Canadian citizens and landed immigrants who were temporarily out of the country on Census Day. This included federal, provincial and territorial government employees posted outside Canada; the staff of Canadian embassies abroad; members of the Canadian Forces stationed abroad; and all Canadians aboard merchant vessels.

1.1 Collection methodology

Since the 2011 Census, a new collection methodology has been used to collect census data. Referred to as the wave methodology, it involves contacting non-respondent households at key times to remind them to take part in the census and to encourage them to complete the questionnaire. In each wave, households are given the information they need to respond. Since every Canadian household is required by law to answer the census questions, this method is designed to encourage people to respond promptly online, while mitigating the risk of a decline in overall response and reducing the need for costly field follow-up.

This methodology varies with the collection method used to distribute the census materials for a given region.^{Note 1} These collection methods are described in the next section. In 2016, Canadian households had the option of responding online, completing a paper questionnaire (mail-back) or contacting the Census Help Line.

1.1.1 Collection methods: Delivery of census questionnaires

The three collection methods used for the Canadian census are mail-out, list/leave and canvasser. To make census collection as efficient as possible, Canada's territory is divided into small geographic units known as collection units (CUs). For the 2016 Census, Canada was divided into approximately 46,000 CUs. There are five types of CUs, and one of three collection methods is assigned to each one. The same collection method is used for all dwellings in a CU.

The collection methods are described below.

1.1.1.1 Mail-out

In CUs where the mail-out collection method is used, the postal system is used to deliver census materials. This delivery method ensures effective, coordinated distribution, without needing to recruit and train a large contingent of enumerators. Mail-out CUs are typically in urban areas. While mail-out CUs now include about 82% of Canadian dwellings, they cover only a tiny fraction of the country's territory. One-quarter of the private dwellings in these CUs are selected to receive the long-form questionnaire; the other dwellings receive the short-form questionnaire.

1.1.1.2 List/leave

List/leave CUs are typically in rural areas. In those areas, enumerators prepare a list of dwellings and deliver the census materials. About 17% of the dwellings in Canada are in list/leave CUs, which cover a large portion of the country's territory. One-quarter of the private dwellings in these CUs are selected to receive the long-form questionnaire. This collection method is also used for collective CUs.

1.1.1.3 Canvasser

Canvasser CUs are either Indian reserves or in remote or difficult-to-access places. To limit the number of often costly and logistically complicated trips that enumerators have to make to these places for follow-up, the enumerators do more than prepare dwelling lists. They also complete a questionnaire with each household on the spot. Canvasser CUs cover just over half of Canada's territory, but only about 1% of dwellings. All private dwellings in these CUs receive the long-form questionnaire.

1.1.2 Census wave methodology

The wave methodology was designed to encourage online response and to offer an alternative for households that do not wish to complete their questionnaire online. This wave approach has many advantages for minimizing non-response and increasing the number of questionnaires completed online, which accelerates questionnaire registration, improves question flow and data capture, and ultimately enhances data quality.

The wave methodology is applied differently depending on the collection method. CUs were therefore consolidated by collection method, and a different wave methodology was developed for each of the three groups. Given the nature of canvasser CUs, a single-wave methodology was adopted for these units. The sections that follow and Figure 1.1.2.1 provide an overview of the wave methodology used for the 2016 Census.

1.1.2.1 Mail-out collection units

In mail-out CUs, Wave 1 involved simply sending out a letter asking households to complete the questionnaire online using the secure access code (SAC) provided or to call an automated system on a toll-free line to have a paper questionnaire mailed to them. The Wave 1 letters were delivered by mail one week before Census Day (i.e., on May 2, 2016).

Wave 2 consisted of a reminder letter sent to all Wave 1 households who had not responded by a certain date, by region. The letter reminded the households that they were required by law to complete the census questionnaire. As the Wave 1 letter did, it also provided the SAC and the toll-free telephone number. It was delivered to households from May 11 to 13.

In Wave 3, from May 19 to 26, a paper questionnaire was sent to non-respondent households. The households could still respond online using the SAC printed on the front cover of the questionnaire. The questionnaire was accompanied by a letter indicating that if the questionnaire was not completed by May 31, 2016, an enumerator would contact the household by telephone or in person to complete the questionnaire. The letter also mentioned that if the household refused to answer the census questions, the case could be referred to the Public Prosecution Service of Canada, which would take appropriate action under the Statistics Act.

Wave 4, which began on June 1, 2016, consisted of field non-response follow-up (NRFU) and an automated reminder call at the beginning of the follow-up period. NRFU is described in section 1.1.3 of this document.

1.1.2.2 List/leave collection units

A different wave methodology was used for list/leave CUs. In Wave 1, enumerators delivered a paper questionnaire to all the dwellings in these CUs from May 2 to 9. The questionnaire also provided a SAC, so that the household had the option of responding online.

In Wave 2, from May 11 to 13, all the dwellings in these CUs received a thank you and reminder card in the mail. These were delivered whether they had responded or not, because sending mail to specific civic addresses without the name of the occupant was generally impossible in these areas.

The last wave involved going directly to field non-response follow-up as of May 20.

1.1.3 Non-response follow-up

As mentioned in the previous section, the last wave in the wave methodology was NRFU. In that wave, enumerators telephoned and visited households that had not responded to the questionnaire. Each non-respondent household for which a telephone number was available received an automated reminder call at the beginning of the NRFU period. This message reminded non-respondents of their legal obligation to respond to the census questionnaire.

NRFU was conducted in person by enumerators or over the telephone by call centre staff. Census employees had information at their disposal to manage their work in the Collection Management Portal. Being a computerized system accessible over the Internet, this portal also facilitated the gathering of information on collection progress and costs.

1.1.4 Dwelling occupancy verification

Before NRFU, field operations were also carried out for dwelling occupancy verification (DOV) of non-respondent dwellings. The purpose of DOV, which began shortly after Census Day, May 10, 2016, was to identify the greatest possible number of dwellings that were unoccupied on Census Day or cancelled (addresses that were not private or collective dwellings) before NRFU started. Identifying such dwellings close to Census Day should make occupancy classification more accurate and easier to perform. DOV also reduces the NRFU workload, since the unoccupied or cancelled dwellings it identifies do not require follow-up.

Nevertheless, errors in classifying a dwelling as occupied or unoccupied do occur during DOV and NRFU. Some dwellings classified as unoccupied are in fact occupied, and some non-respondent dwellings are unoccupied. As a result, another process, the Dwelling Classification Survey (DCS), is carried out after NRFU. It determines the occupancy status of a sample of dwellings for which no completed questionnaire was received (unoccupied dwellings, non-respondent dwellings or unresolved cases), and it estimates occupancy rates for all dwellings in the same situation across the country. The survey results are used to adjust the Census of Population counts during processing. More information on the DCS is provided in section 3.6.

1.2 Questionnaires and forms

Various questionnaires and forms are used to collect data for the Canadian census, and respondents have the choice of completing the census questionnaire online or using a paper questionnaire.

Visitation Record (VR) is used to list every occupied and unoccupied private or collective dwelling, agricultural operation and agricultural operator in the areas of the country where a list of dwellings is created before questionnaires are delivered (i.e., in list/leave collection units; see section 1.1.1.2). The VR serves as an address list for field operation and control purposes during data collection.

Form 2A is the basic short-form questionnaire used to enumerate private dwellings. Each household is asked to list all household members who belong to the census population and to answer questions for them.

Forms 2A-L and 2A-R are the long-form questionnaire. The questions on form 2A are also on these forms, followed by additional questions on various subjects such as education, employment and dwellings. Form 2A-L is distributed to 25% of Canadian households in mail-out areas and list/leave areas, as described in sections 1.1.1.1 and 1.1.1.2; these are the long-form sample households. Form 2A-R has nearly all the same questions as form 2A-L and is used in areas where canvassing is the collection method. All households in these areas are included in the long-form sample.

Form 2C is used to enumerate Canadians posted abroad. Form 2C has the same questions as form 2A.

Form 3A is an individual census questionnaire used to enumerate persons in collective dwellings. It can also be used to enumerate usual residents in a private household who prefer to complete their own census questionnaire rather than be included in a form 2A.

1.3 Collection response rate

The overall collection response rate for the 2016 Census of Population was 98.4%. This rate was calculated directly from the collection results (as of August 4, 2016), i.e., before data processing and quality verification were completed. It represents the number of private dwellings for which a questionnaire was returned, divided by the number of private dwellings that enumerators coded as being occupied. The collection response rate for the long-form sample was 97.8% (for more information, see the 2016 Census of Population collection response rates).

Note

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