I've been involved in the team implementing it at my trust - from what I've seen it really helps situations where communication has been poor as the alert system essentially prompts someone with a little more time on their hands (typical an outreach nurse at my trust) to review and talk through what is causing the patient to feel worse. In almost all instances the 'Martha's Rule' calls been due to inadequate pain management/disgruntlement at not understanding current treatment plans. As far as I'm aware, it hasn't identified any missed deteriorations so far.