The risk adjusted mortality rate (RAMR) is a mortality rate that is adjusted for predicted risk of death.
It is usually utilized to observe and/or compare the performance of certain institution(s) or person(s), e.g., hospitals or surgeons.
For example, for a group of patients first we need to find the observed mortality rates for all the hospitals of interest.
Once we have the above three rates, then we can utilize the above formula to find the risk adjusted mortality rate which will reflect the actual mortality rate of a particular hospital without being biased from the observed mortality.
[1] The BBC produced a table in 2011 comparing mortality on various measures across all NHS acute trusts.