Standardization is used to reduce the effects of confounding variables like age and gender
Standardization is necessary to compare mortality or morbidity rates of populations with different age or gender distribution
Comparing the crude rates of these populations would be misleading due to different age and gender distribution
Direct and indirect methods of standardization exist
These methods compare the mortality or morbidity rate of the measured population to the rates of a standard population
Direct standardization
Determine the age-specific mortality rates of your measured population
Apply these mortality rates to the standard population to get the “expected” mortality rate
Compare the expected mortality rate of the standard population to the measured mortality rate of the measured population
Indirect standardization
It is used instead of direct standardization if there is insufficient data or if the population is small
Yields the standardized mortality ratio (SMR)
SMR = the number of deaths in the study population / the number of deaths that would be expected in the study population if that population had experienced the death rates of the standard population
SMR allows comparison of mortality rate with the mortality rate of the standard population or other standardized population
