Dr. Saleh said: “In engineering, the reliability of a component or process is defined as the probability that it is still operational at a given time. The time it takes for a component or process to fail is referred to as its time-to-failure and this shows similarities to the time-to-violent-death of Roman emperors.”
Dr. Saleh found that Roman emperors faced a high risk of violent death during their first year of reign, a pattern also seen when engineering components fail early, often as a result of a failure to function as intended or, in the case of an emperor, meet the demands of their role. The risk of death stabilised by the eighth year but increased again after 12 years of rule, a pattern similar to the failure of components because of fatigue, corrosion or wear-out. When data points were aligned on a graph, the failure rate of Roman emperors displayed a bathtub-like curve, a model widely seen with mechanical and electrical components.