Astudy compared miami, florida and boston, massachusetts with respect to cancer mortality between the ages of 18 and 99 years. in miami, the crude rate for death from cancer was 220 per 10,000 population per year. in boston, the crude rate for death from cancer was 150 per 10,000 population per year. one concern raised by this study was the possible effect of different age distributions in the two cities. you check on the age distributions and find that boston’s population had a much greater percentage of young people (college students and young professionals), while miami had a larger percentage of people in the older age brackets (retired persons). because of the difference in age distribution, the authors of the study used direct standardization to calculate age-adjusted rates using the age distribution for the us population in 2000 as the standard. in miami, the age-adjusted rate for death from cancer was 108 per 10,000 population per year. in boston, the age-adjusted rate for death from cancer was 175 per 10,000 population per year. did the differences in age contribute to the observed difference in the crude rates ? no, the difference between the adjusted rates for boston and miami is almost the same as the difference between the crude rates yes, the crude rate is substantially higher in miami, but when you adjust for the age differences, boston actually has a higher age-adjusted rate of cancer death