All are true of standardised moality ratio except
ref: Park&;s 23rd edition pg 58 it is expressed as a ratio (usually in percentage) SMR is a ratio of the total number of deaths that occur in a study group to the number of deaths that would have been expected to occur if that study group had experienced the death rates of a standard population (or reference population).
Expressed as rate per rate
can be adjusted for age
can be used for events other than death
Ratio of observed deaths to expected deaths
Epidemiology