Ask an Epi: Crude Birth Rate

Question: What is crude birth rate

Simply put, crude birth rate is the total number of births in a population divided by the total number of individuals in a population over a given period of time.  

Crude birth rate is helpful when determining the birth rate of a specific population. Comparing crude birth rates between different populations, however, can be misleading. This is because the populations have different characteristics that may distort the results. For example, a location with a high population of people older than child-bearing age would naturally have a much lower birth rate. Comparing this location's birth rate to other locations, without also noting their different demographics, can paint an inaccurate picture.

Below is an example of a crude mortality rate. This chart features LiveStories data, which looks at the total number of people who died from diabetes in a population of 100,000 people. 

Diabetes Crude Mortality Rate (UCD)

Source: Center for Disease Control and Prevention, CDC Wonder

Question: What is the difference between crude birth rate and age-adjusted birth rate?

While crude birth rate reflects the birth rate of a single population, age-adjusted birth rate can be used when making side-by-side comparisons between different populations. This is possible as age-adjusted rates take into account the unique demographic makeup of a given population. 

Below is an example of an age-adjusted mortality rate. This chart features LiveStories data, which looks at the total number of people who died from diabetes in a population of 100,000 people. 

Diabetes Age-Adjusted Mortality Rate (MCD)

Source: Centers for Disease Control and Prevention, CDC Wonder

Because Florida has a much older population than Utah, age-adjusting the mortality rate places the state significantly lower in comparisons. The age-adjusted chart also shows a significantly lower diabetes mortality rate overall in recent years than the crude rate chart. This is because diabetes is becoming increasingly concentrated among older Americans—who are weighted less in age-adjusted mortality statistics. 

 

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Sofia Husain is a Customer Success Manager and Epidemiologist at LiveStories. She is an advocate for customers, helping them use LiveStories most effectively by understanding their data analysis and communication needs.