for the birth cohort 1948-1958, yielding an adjusted incidence rate of (87/69.4) * 4.22 = 5.29. The overall rate from Step 4 was used as the reference rate in order to facilitate comparisons across birth cohort for individual health districts and counties, and to allow comparisons among health districts and counties within birth cohort. See Box D.1 for a description of the Idaho population by health districts.
Step 11. The adjusted rates for the state of Idaho were calculated by birth cohort using the standardized incidence ratio for that birth cohort (observed/expected), with expected cases based upon age- and sex-specific rates for all birth cohorts
BOX D.1 Description of Idaho Population
The population of the state of Idaho in 1996 was estimated to be 1,189,251, made up of 594,604 males and 594,647 females (U.S. Bureau of the Census). Idaho comprises 44 counties grouped into seven health districts. The composition of the health districts and population estimates by sex are shown below: