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Case Study #261 — 300 Software Failure Case Studies

Canada's ArriveCAN app bugs and cost overruns

Canada's mandatory COVID-19 travel-declaration app, ArriveCAN, incorrectly told an estimated 10,000 fully vaccinated travelers to quarantine, and a subsequent audit found its development cost had ballooned to roughly CAD $54 million for what auditors said should have been a much simpler build.

2022
When it happened
Government
Sector
#261 of 300
Ranked by documented impact
01 — What Happened

The damage was public. The root cause was preventable.

Canada's mandatory COVID-19 travel-declaration app, ArriveCAN, incorrectly told an estimated 10,000 fully vaccinated travelers to quarantine, and a subsequent audit found its development cost had ballooned to roughly CAD $54 million for what auditors said should have been a much simpler build.

Government
Sector affected
2022
Date of the event
#261
Rank in the 300 Software Failure Case Studies
2
Distinct root-cause clauses identified below
02 — The Root Cause

What the software actually got wrong

A software bug in the app's vaccination-status logic caused it to misclassify some vaccinated travelers as needing to quarantine, and Canada's Auditor General found poor program management and inadequate documentation contributed to both the technical errors and the program's runaway costs.

01Root Cause

A software bug in the app's vaccination-status logic caused...

What Happened

A software bug in the app's vaccination-status logic caused it to misclassify some vaccinated travelers as needing to quarantine

How Requs AI Catches This

Requs AI Edge Case flags this exact pattern at the requirements and architecture stage — before a single line of code implementing it exists — so the assumption behind it gets challenged while it is still cheap to fix.

02Root Cause

Canada's Auditor General found poor program management and inadequate...

What Happened

Canada's Auditor General found poor program management and inadequate documentation contributed to both the technical errors and the program's runaway costs

How Requs AI Catches This

Requs AI Software FMEA traces this failure mode back to the system-level hazard it feeds, tagging it against the Common Defect Enumeration so it surfaces in review instead of in the field.

03 — How This Gets Caught Before It Happens

Beyond code coverage and "shall" testing

Root causes like this one rarely show up in code coverage or requirements-compliance testing, because nobody wrote a requirement anticipating the specific edge case that broke. Requs AI Edge Case and Requs AI Software FMEA are built to surface exactly this class of overlooked failure mode — before the software is written.

Requs AI Edge Case

Surfaces this before code exists

Identifies edge cases like this one at requirements and architecture time, using the Common Defect Enumeration to catalog failure patterns seen across hundreds of real-world software failures — including this one.

Requs AI Software FMEA

Connects the failure mode to the hazard

Traces this class of root cause directly to the system-level hazard it can produce, so a defect pattern like this one gets flagged during design review instead of after it ships.

Find the overlooked root causes before they ship.

Schedule a demonstration, or explore how Requs AI Edge Case and Software FMEA use the Common Defect Enumeration.