To calculate age standardized rates, one must first obtain age-specific rates for the population being studied. These rates are then weighted according to a standard population, which is a hypothetical population structure. The World Health Organization (WHO) often provides such a standard population. The age-specific rates are multiplied by the corresponding weights of the standard population, and the results are summed to give the age standardized rate. This process ensures that comparisons are on a level playing field, regardless of the underlying age distributions.
