If your claim to Canadian citizenship runs through a grandparent, great-grandparent, or older relative, an immigration officer has to follow it one generation at a time. For each parent and child in your line, the officer decides whether the link is more likely than not to be real.

That bar is called the balance of probabilities. Immigration, Refugees and Citizenship Canada (IRCC)’s decision-making guidance sets it at anything above 50%. The same guidance tells officers to presume your evidence is true unless they have a valid and compelling reason to doubt it, and it warns them against being “overly suspicious.”

The guidance sets a framework, but the decision rests with the officer who reviews your file. That officer interprets the law, weighs your documents, and judges whether your case meets the standard. With so much depending on one person’s reading of the evidence, applicants put real effort into making their file as strong as it can be.

You still carry the responsibility of submitting adequate proof. If the evidence on a point comes out even, the officer treats that point as unproven.

The officer checks every link in two ways: how much each document proves, and whether each generation connects to the next.

The officer weighs each document on its own merits

Every document in your file gets measured for how much it proves. IRCC’s decision-making guidance has officers ask questions like these:

• Is this the best document available?
• Did an authority with no stake in the outcome issue it?
• Is it the record closest in time to the event?

IRCC also sorts citizenship by descent documents into two tiers, primary and secondary. The tiers describe how much weight a document carries as evidence, not where it came from. A provincial birth certificate is a primary document. A baptismal record or census entry is secondary, even when the church or archive that holds it issued the copy.

Officers have to consider every relevant document you submit. Primary documents still carry the most weight, and no single secondary document can replace a missing primary one. CIC News has published IRCC’s full list of primary and secondary documents.

Vague or indirect evidence carries less weight than direct, detailed evidence. The guidance lists red flags for officers:

• spelling errors on an official document
• missing signatures or dates
• conflicts with other records
• signs of alteration

Officers treat clear colour copies as originals unless something casts doubt on them. If a credibility concern could affect the decision, the officer has to give you a chance to respond.

IRCC’s quality assurance program also picks some applications at random for an interview. At that interview, officers check original documents and can request more evidence, up to DNA testing to confirm parentage.

Applicants who settle conflicts between records before filing, with a corrected record or