Standardization

The objective of standardization is the compare the rates of a disease (or outcome) between population which differ in underlying characteristics (age, sex, race, etc) that may affect the overall rate of disease; In essence it's another way to account for confounding.

There are two approaches to Standardization of Rates:

Direct Standardization (Most Common)

w_i are the frequency from "standard" population, r_i are rates from testing population. Very similar to the "weighted average" method from the last chapter.

• Stratum-specific rates (r_i) from population under study
• Strata distribution (w_i) from a "standard" population
• My rates, standard weights

There are many choices for the 'standard' population.

• Internal Standard - one of the groups under study, total population of the study
• External standard - outside, a larger group (ex. US population)

Indirect Standardization

w_i are the frequency from testing population and r_i are rates from "standard" population.