WISQARS™ Fatal Injury Mapping Help Menu
3.1 Crude Rate Calculations
Crude rates are the simplest type of rate provided by WISQARS Fatal Injury Mapping. They are useful when you want to map observed statewide or county-level death rates. Crude rates can be calculated for an entire population (for example, all persons in California) or for a subgroup (for example, all males in California). They can also be calculated for a specific age group in a population (for example, all persons in California who are 20–29 years old) or in a subgroup (for example, all males in California who are 20–29 years old).
Once the population has been selected (along with an optional age range), the crude rate is calculated by dividing the count of injury deaths by the total number of persons in the selected population. (When the reporting period covers multiple years, injury deaths and populations are first summed over all years before dividing.) The result is then multiplied by 100,000.
Example: Crude Rate of Motor Vehicle Traffic Fatalities in California, Years 2008–2014
- Total Motor Vehicle Traffic Deaths in California from 2008 through 2014 = 21,854
- Total Population in California from 2008 through 2014 (summed across years) = 263,818,096
- Crude Rate = (21,854 ÷ 263,818,096) × 100,000 = 8.28 per 100,000 population
The calculated crude rate answers the question: How many deaths occurred per year for every 100,000 persons in the selected population? In the example above, the crude rate indicates that 8.28 motor vehicle traffic fatalities occurred per year for every 100,000 persons residing in California (for the period 2008–2014).
Your selections can sometimes narrow your request to the point that a corresponding population is not present in one or more states or counties. In such instances, the crude rate is not defined.