What does it mean for a court to review an immigration decision on a 'reasonableness' standard?

Reviewing a decision on a "reasonableness" standard means the Federal Court is not asking whether it would have reached the same conclusion itself. Instead, it asks whether the decision-maker's reasoning was transparent, intelligible, and justified in light of the facts and the law that applied, and whether the outcome falls within a range of defensible conclusions a reasonable decision-maker could have reached on that record.

This is a deferential standard, and it is the one applied to most immigration officer decisions. It means a court will not overturn a decision simply because it might have weighed the evidence differently, or because a different but equally reasonable outcome was also available. What it does look for are genuine flaws in the reasoning itself — internal contradictions, a failure to grapple with key evidence, or conclusions that do not logically follow from the reasons given.

A narrower set of issues, such as some questions of procedural fairness, is reviewed on a stricter basis instead. Understanding which standard applies to a particular argument matters, because it shapes what kind of flaw actually needs to be shown to succeed.