Marine International Freight Origin and Destination Survey

Detailed information for July to December 2001

This survey collects data on international shipping, that is, vessels involved in international transport of commodities that load or unload their cargoes in Canadian ports.

Data release - January 17, 2003 (this release includes revisions to January-June 2001)

• Description
• Data sources and methodology
• Data accuracy

Description

This survey collects data on international shipping, that is, vessels involved in international transport of commodities that load or unload their cargoes in Canadian ports. The data are used by Statistics Canada as input to the Canadian System of National Accounts, by Transport Canada, other federal and provincial departments, transportation companies, consulting firms and universities. The information is used for the analysis of transportation activity, for marketing and economic studies, as well as industry performance measures.

Statistical activity

This statistical activity is part of a set of surveys measuring various aspects of activities related to the movement of people and goods. These surveys are grouped as follows:

Transportation by air includes records related to the movement of aircraft, passengers and cargo by air for both Canadian and foreign air carriers operating in Canada as well as the financial and operating characteristics of Canadian air carriers. These data are produced by the Aviation Statistics Centre.

Transportation by rail includes records relating to rail transportation in Canada, and between the United States and Canada.

Transportation by road includes records relating to all road transport in Canada. In addition to surveying carriers and owners of registered motor vehicles, certain programs rely on aggregation of provincial and territorial administrative records.

Subjects

• Transportation
• Transportation by water

Data sources and methodology

Target population

The universe includes vessels used for international shipping that enter and leave Canadian ports with the exception of fishing boats registered in Canada or abroad, maintenance and service ships such as icebreakers, research vessels and other non-commercial vessels such as hospital ships.

Instrument design

This methodology does not apply.

Sampling

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

This methodology does not apply.

Data sources

Responding to this survey is mandatory.

Data are extracted from administrative files.

The paper A6 General Declaration and A6A Manifest must be presented to Canada Border Service Agency (CBSA) for every vessel departing for any port or place outside of Canada. A6/A6A data are provided by the CBSA to Statistics Canada. Where cargo is to be loaded/unloaded at more than one Canadian port, the master or agent will report to CBSA, using the paper A6/A6A, only that cargo which is loaded/unloaded at the subsequent(s) port(s). Paper copies of those documents are mailed weekly to Statistics Canada, Ottawa, by local CBSA officials. In lieu of the A6 and attachments, some data are provided by shipping lines and/or port authorities to Statistics Canada electronically.

Error detection

Upon receipt, the documents are manually sorted and edited for consistency and accuracy of reported data. The capture and editing procedures involve the assignment of codes, a check for consistency of information in comparison to previous trends and port activities, the use of reference materials for missing or questionable data and the telephone follow-up of unsatisfactory reports. In this final step, the shipping companies, their agents or the Customs offices involved may be contacted. The data is then subjected to computerized edits designed to ensure accuracy and internal consistency.

Imputation

Manual imputation of reports or particular field is used to compensate for missing data based on expert subject matter knowledge. Imputation is mostly done for missing records.

Quality evaluation

The quality of the data is evaluated using trend analysis and comparisons of the data with statistics from other sources including information published by port authorities.

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. Data for a specific industry or variable may be suppressed (along with that of a second industry or variable) if the number of enterprises in the population is too low.

Revisions and seasonal adjustment

Semi-annual estimates are provided. The data for the previous period are revised if necessary. Seasonal adjustments are not made to the data.

Data accuracy

All statistical surveys are subject to errors. The total error of a survey is defined as the difference between the survey estimate and the actual value for the target population. Survey errors can be classified as "sampling" or "non-sampling" errors. The marine transport surveys are censuses and are therefore not subject to sampling errors.

There are four main types of non-sampling errors:

i. Coverage errors (when the survey frame does not thoroughly cover the target population);
ii. Response errors (when a respondent provides inaccurate information);
iii. Non-response errors (when a respondent does not respond to all or part of the questionnaire) and,
iv. Processing errors (errors made during data capture, coding, and editing).

With respect to coverage error for the Marine International Freight Origin Destination Survey, customs rules apply to all ships arriving from or departing for foreign ports. However, Statistics Canada has only limited tools for identifying missing shipping documents.

The survey does have significant exposure to response error, particularly in terms of the reported commodities. The marine carrier of international cargo is not always able to provide descriptions that are sufficiently detailed to accurately code the commodity. Terms such as general cargo are often used in cases where the carrier is unsure of the exact contents of a container or when there are a number of commodities being transported in one shipment. As result, residual categories such as "Other manufactured and miscellaneous goods" and "Other chemical products and preparations" may be overestimated while the true commodity is understated. Respondents may also use incorrect conversion factors in estimating the weight of a shipment.

In regards to non-response errors, while it is assumed that the reporting to the Canada Border Services Agency (CBSA) of international traffic is fairly comprehensive, there are occasions when reports are not forwarded to Statistics Canada, particularly for ports in the Canadian Arctic and other remote areas that do not have local customs offices.

Processing errors may occur during data entry, including errors in transcribing and coding information and in converting cargo quantities from non-weight units (e.g., barrels or cubic metres to kilograms). Errors may also be introduced during editing and imputation procedures that are used to correct data that appear to be erroneously reported or partially reported. A number of techniques are used to detect and resolve these errors including micro and macro analysis of the data for congruency and consistency with information acquired from other sources (e.g., cargo statistics from port authorities and economic statistics from other Statistics Canada divisions).