Background The risk adjustment in congenital heart surgery-1 method (RACHS-1) and the aristotle complexity score are widely used around the world and have been shown to correlate reasonably well with cardiac surgery outcome.The aristotle complexity score include two scores:the aristotle basic complexity score (ABC) and the aristotle comprehensive complexity score (ACC).Objective Compare the two scores application and their advantages.Content RACHS-1 was a better predictor than ABC with regard to the ability to predict mortality and morbidity.While ACC was a better predictor than RACHS-1.In order to achieve similar performance,RACHS-1 need to be further adjusted on age,prematurity,and major extracardiac abnormalities.Trend Efforts are taken to refine the two systems.They may eventually unify and become one.