Even with good frameworks, several mistakes commonly undermine brittleness testing:
Surface Testing Only Testing only visible components misses deep structural brittleness. Push beyond obvious elements to underlying dependencies.
Nancy tested her business and felt confident—multiple products, various price points, global customers. But she stopped at surface level. Deeper testing would have revealed all products required the same rare component with a single supplier. When that supplier failed, her entire business stopped.
Optimism Bias Assuming "it won't happen here" or "we'll figure it out if it does" prevents honest brittleness assessment.
Paul's brittleness test revealed dangerous dependence on key employees. But he dismissed it—"they've been here for years, they're not leaving." When three key people left simultaneously for a competitor, his optimism bias cost him dearly.
Testing Without Action Identifying brittleness without addressing it might be worse than ignorance—you see the train coming but don't step off the tracks.
Martha conducted thorough brittleness tests quarterly, documenting every vulnerability. But she never acted on findings, always planning to "address them next quarter." When brittleness finally triggered, her detailed documentation only highlighted her inaction.