When building a Future Reality Tree (FRT), a solution is “injected” to a string of cause-and-effect in order to neutralize it. If there is no check about a potential new problem created by the injected solution, it could be that ironically the solution to the first problem creates a new one, potentially worse. That would be ironic! The good practice is to assess if an unexpected New Undesirable Effect can be created, in what is called a Negative Branch, which is a string of cause-and-effect.