What is on these maps?
On these colored maps, you can see the case rates per 1,000 residents.
This means that we have calculated how many confirmed cases there are per 1,000 residents.
This allows us to compare the urban areas with rural areas while taking into account their population.
The darker the orange is, the higher the case rate.
Examples
So if a county is rural and only has 1,000 residents and 1 case, they would have a case rate of 1. If the same county had 5 cases, their case rate would be 5.
Similarly, if a county has 5,000 residents, and they have 1 case, then their case rate would be a fifth of 1, which is 0.2.
Why did you pick orange?
Because orange is the color of our center. We chose not to pick red and green because this generally makes people think that green is good and red is bad.
Why did you not pick the standard “per 100,000 residents for your rate?
We chose not to use 100,000, which is usually the standard, as the rates would make very small rural counties look worse than they are.
An example of this would be a county with 1,000 residents: for a rate per 100,000, their case rate would go up 100 for each case. So 1 case would be a rate of 100, 2 cases would be 200, etc.
But if you compare that with Fulton county, which has 1 million residents, then it seems unfair: if they have 400 cases, their rate would only be 40. This would make the small rural county look very bad.
The 100,000 rate is common and reliable for larger cities and countries. In Georgia, we have many rural counties, but all have more than 1,000 residents, so we picked 1,000 as our standard.
Was there a different color scale before?
Yes. On April 8th, our Covid-19 Team decided to change the scale we devised end of March, as the case rates were going up in Georgia resulting in a dark map. On these darker maps, it was hard to distinguish between high Covid-19 rates and very high Covid-19 case rates, as they were a similar dark brown. We used the quintile approach to change the scale in a reliable way that is still clear.