An internal Canada Border Services Agency briefing note warns the lack of reliable data might be an obstacle to compiling a comprehensive record of almost everyone who enters and leaves the continent.
The entry-exit tracking system, to be phased in over the next two years, is a crucial feature of the perimeter security pact unfurled with much fanfare a year ago.
The deal is intended to help smooth the passage of travellers and cargo across the Canada-U.S. border while beefing up continental security.
The tracking system involves exchanging entry information collected from people at the land border — so that data on entry to one country would serve as a record of exit from the other.
In addition, Canada plans to collect information on people exiting by air — something the United States already does — by requiring airlines to submit passenger manifest data for outbound international flights.
The two countries plan to use the data to detect people overstaying their visas and to determine whether those subject to removal or departure orders have actually left.
It will also help gauge whether someone has met residency requirements for citizenship by measuring how long they have been present in the country. And it could help prevent people from assuming one identity in Canada and another in the U.S.
Currently, commercial airlines flying into Canada must provide the Canada Border Services Agency with what's known as Advance Passenger Information and Passenger Name Record data.
API includes the traveller's name, date of birth, citizenship or nationality, and passport or other travel document information. PNR information features additional details such as the passenger's address, itinerary and ticketing data.
However, there have long been concerns about the accuracy and reliability of such information — a problem acknowledged by the border agency briefing note, obtained by The Canadian Press under the Access to Information Act.
"The quality of the data currently being submitted through Advance Passenger information could create challenges for the successful matching of the exit and entry records," says the February 2012 note.
In an October 2007 report, the federal auditor general highlighted problems with advance passenger data.
It noted a December 2006 exercise in which the border agency compared the advance data received from four flights with the actual passengers who arrived.
"The study found that 37 per cent of data transmitted by the airlines for these flights was not accurate, potentially hindering the proper identification of high-risk travellers," says the auditor's report.
At the same time, civil libertarians argue that such error-riddled information can lead to travellers being incorrectly pegged as security threats.
The border agency's Andrew Lawrence, director of the entry-exit program, said he is focusing on a current Canada-U.S. pilot project involving exchange of information collected at four ports of entry — two on the B.C.-Washington border, two on the Ontario-New York border.
"I think as we move forward, and based on the outcome of the pilot, we will put together a strategy to address information quality for the entire entry-exit program," he said in an interview.
Ensuring data quality is one element of a 12-point statement of privacy principles guiding the Canada-U.S. security pact.
Development of the entry-exit program will entail legislative and regulatory amendments for the collection, use, disclosure and storage of data on travellers, says the border agency briefing note.
In addition, an information-sharing agreement will be negotiated with both the U.S. and commercial airlines.
The border agency has studied similar programs in other countries to identify the best means of making the system work without unduly inconveniencing the airline industry, the note adds.
The current pilot project involves border crossing records of third-country nationals — not U.S. or Canadian citizens.
"It's a little premature to draw any conclusions with respect to the information because we will be doing subsequent exchanges with the United States in the coming months," Lawrence said.
By June 30, 2014, the entry-exit program will be expanded to include U.S. and Canadian citizens.
For the time being it will not apply to those travelling by rail or water.