A chain always fails by a weak link. It’s not possible for it to fail in any other way. Cutting it creates a weaker link, for example. Identifying the weak link

A chain always fails by a weak link. It’s not possible for it to fail in any other way. Cutting it creates a weaker link, for example. Identifying the weak link and understanding why it isn’t failing would be the root cause of success. Identifying what stress on the weak link causes it to fail, would be the root cause of failure.