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Case Study #153 — 300 Software Failure Case Studies

UK Child Support Agency computer system failure

The UK's Child Support Agency's new computer system, built by EDS, created a massive backlog of unresolved child-maintenance cases and years of incorrect payments, ultimately contributing to the agency's abolition.

2003
When it happened
Government
Sector
#153 of 300
Ranked by documented impact
01 — What Happened

The damage was public. The root cause was preventable.

The UK's Child Support Agency's new computer system, built by EDS, created a massive backlog of unresolved child-maintenance cases and years of incorrect payments, ultimately contributing to the agency's abolition.

Government
Sector affected
2003
Date of the event
#153
Rank in the 300 Software Failure Case Studies
1
Distinct root-cause clause identified below
02 — The Root Cause

What the software actually got wrong

The new case-management software could not correctly process the agency's complex child-support calculation rules and struggled to migrate legacy cases, causing the backlog to balloon into the hundreds of thousands rather than shrink as intended.

01Root Cause

The new case-management software could not correctly process the...

What Happened

The new case-management software could not correctly process the agency's complex child-support calculation rules and struggled to migrate legacy cases, causing the backlog to balloon into the hundreds of thousands rather than shrink as intended.

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.

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.