This is the most widely used measure to determine the overall health of a community. We compare mortality for a given disease to the affected population to evaluate mortality trends. National death rates are usually computed per 100,000 population. For example, in 1989 the total deaths from CHD were 498,021. This resulted in a crude death rate of 200.6 per 100,000 population.
Crude rates are simply the ratio of mortality to population for any given year.
Age-adjusting gets rid of fluctuations in the data due to differences in the age distribution of the population. The base year that the federal government and health organizations have used for almost 60 years is 1940. In 1940 there were 132 million Americans. By 1998 the population had more than doubled to 270 million. In 1940 the proportion of Americans over 65 was only 6.8 percent.