Asphalt Roofing

Detailed information for December 2001

The monthly survey, Asphalt Roofing, measures quantities of selected asphalt roofing products that are produced and shipped by Canadian manufacturers including destination of shipments by province and exports.

Data release - January 30, 2002

• Questionnaire(s) and reporting guide(s)
• Description
• Data sources and methodology
• Data accuracy

Description

This survey measures, on a monthly basis, the quantities of selected asphalt roofing products that are produced and shipped by Canadian manufacturers and the destination of shipments by province and exports.

The quantities of asphalt roofing products produced and shipped are used as an indicator of the economic condition of this industry and trends in the housing market, as an input to Canada's Gross Domestic Product and as an input into macro- and micro-economic studies to determine market shares and industry trends. Data are used by the business community, trade associations (including the Canadian Asphalt Shingle Manufacturers' Association) federal and provincial departments and international organizations.

Reference period: Month

Collection period: Each month

Subjects

• Construction
• Construction materials
• Manufacturing
• Petroleum and coal

Data sources and methodology

Target population

The target population for this survey includes manufacturers in Canada of asphalt roofing products as defined in the Standard Classification of Goods (SCG), that report these products to the Annual Survey of Manufacturing and Logging Industries or ASML (record number 2103). This means that estimates from this monthly survey do not cover the entire universe of Asphalt roofing producers in Canada because the ASML does not survey all businesses. Instead, the ASML uses administrative data to cover the small and medium-sized establishments. These manufacturers are not part of this monthly survey.

Instrument design

The questionnaire was developed in collaboration with the Canadian Asphalt Shingle Manufacturers' Association in order to fulfill their needs. Regular dialogue is maintained with the association and the respondents, and every effort is made to ensure that the questions asked are relevant and can be answered by the manufacturers.

Sampling

This survey is a census with a longitudinal design.

This methodology does not apply.

Data sources

Responding to this survey is mandatory.

Data are collected directly from survey respondents.

Data are collected each month from survey respondents using a mail-out / mail-back process. Data capture and preliminary editing are performed simultaneously to ensure validity of the data. Businesses from whom no response has been received or whose data may contain errors are followed-up by telephone or fax.

Under normal circumstances, data are collected, captured, edited, tabulated and published within 4 weeks after the reference month.

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

Error detection

In order to detect errors and internal inconsistencies, automated edits are applied to captured data to verify that totals equal the sum of components and that the data are consistent with the previous month's data. Data that fail the edits are subject to manual inspection and possible corrective action.

In addition, subject matter experts analyze the data at a more aggregate level to detect and verify any large month-to-month or year-over-year changes for the industry.

Imputation

Missing data for the current month are imputed automatically by applying to the previous month's value, the month-to-month change observed for the same period in the previous year, for the unit in question. However, an option exists for analysts to manually override this imputation with a better estimate based on pertinent knowledge about the industry or the business.

Quality evaluation

Survey results are analyzed to ensure comparability with patterns observed in the historical data series and the economic condition of the industry. Information available from other sources, such as the Monthly Survey of Manufacturing (record number 2101), the Building Permits survey (record number 2802), the media, other government organizations, and industry associations, are also used in the validation process.

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.

Confidentiality analysis includes the detection of possible direct disclosure, which occurs when the value in a tabulation cell is composed of a few respondents or when the cell is dominated by a few companies.

Data accuracy

All survey data, from whatever source, are subject to error such as errors related to coverage, bad response, processing and non-response.

In the case of the Asphalt Roofing Survey, there is a possibility of under-coverage because the frame is derived from the ASM which lags behind the current survey. However, the risk of under-coverage is minimal because of advance information from the ASM frame, feed-back from MSM and information from other sources such as the Canadian Asphalt Shingle Manufacturers Association.

Response and processing errors do not easily lend themselves to quantification. Where they are detected, they are corrected. Sometimes the data are revised at a later date. On a monthly basis, late or non-responses are imputed using a variety of methods, the most common being trend analysis.