Integration Failure Pattern (System of Systems Breakdown)

The pattern where individually functional components fail when combined, because the interfaces between components introduce failure modes that don't exist in any individual component. The mechanism: (1) each component is developed and tested independently, (2) each component works correctly in isolation, (3) when components are integrated, the interactions between them produce unexpected behaviors (timing conflicts, data format mismatches, assumption collisions, resource contention), (4) these emergent failures are harder to diagnose than component failures because they exist in the spaces between components, not within them. The Healthcare.gov launch (2013) is the canonical modern example: multiple independently developed systems by different contractors, each tested in isolation, failed catastrophically when integrated. The pattern is especially common when different teams, organizations, or vendors build different parts of a system, because each team optimizes for their component's requirements without full visibility into how their component interacts with others.

When to use it

When combining systems, teams, or technologies from different sources. When planning large-scale system integrations or migrations. When multiple vendors or teams are building parts of a unified system. When investigating failures that occur at component boundaries.

How it can help

Provides specific integration risk management principles. (1) Test integration early and continuously—don't wait until all components are complete to discover interface failures. (2) Define interface contracts rigorously and test against them independently of component internals. (3) Build integration environments that mimic production as closely as possible. (4) Assign 'integration owners' whose job is to manage the spaces between components, not the components themselves. (5) Budget at least 30% of project time for integration—most projects budget 5-10% and consistently overrun. The key insight: integration problems live in the 'white spaces' on org charts—the areas between teams where no one has explicit ownership.