Return to Chapter 4 Pg 4 Confounding

Direct Method:  Specific rates applied to standard population
This weighted average of specific rates with the standard population provides a rate of the number of events that
would have been expected if the populations compared had identical distribution of the variable of interest.

Indirect Method:  Standard rates applied to specific population distribution or structure of interest
The weighted average of category specific expected number of cases is calculated by multiplying the stratum-specific rates by the weights of each category.  This results in a ratio of observed number of cases to the expected number of cases.