Rockall et al. identified independent risk factors[1] in 1996 which were later shown to predict mortality accurately.
The scoring system uses clinical criteria (increasing age, co-morbidity, shock) as well as endoscopic finding (diagnosis, stigmata of acute bleeding).
It is named for Professor Tim Rockall, who was the main investigator and first author of the studies that led to its formulation.
A convenient mnemonic is ABCDE - i.e. Age, Blood pressure fall (shock), Co-morbidity, Diagnosis and Evidence of bleeding.
[citation needed] Total score is calculated by simple addition.