Understanding benchmarks for population breakouts

When viewing population breakouts on the framework screen, you might wonder why the benchmark value is the same for each population breakout. Let's explore the visualization: 

The screenshot below shows Life Expectancy in Atlanta, Georgia, compared with the national benchmark. This screen shows that in Atlanta, the average life expectancy for the total population is 78.1 years, compared with 77.7 years nationally. The population breakouts are also benchmarked to the total population. In other words, when looking at the Black or African American population, the visualization shows that the life expectancy is 73.5 compared with the total population benchmark of 77.7 years. 

Why don't we benchmark Black and African Americans in Atlanta, GA, against the Black and African American Populations nationally? These visualizations aim to shed light on disparities. By showing the variance from the total population, these disparities are more evident.