rates used to summarize the *morbidity or *mortality experience of a population. Age-specific rates and population structures from a study population and a reference or *standard population are used to produce a weighted average. Standardized rates can be used to compare the health experience of populations with different structures. Direct standardization requires application of age-specific rates from a study population to a reference population structure (e.g. the European standard population) to produce a (directly) standardized rate. Indirect standardization requires application of age-specific rates from a standard population (e.g. England and Wales) to a study population structure to produce an expected morbidity or mortality rate. Compare crude rate.