So yesterday Donald Trump said in a press conference that "areas of our country that have been hotspots have done much more testing on a per capita basis than South Korea." I know that Per Capita means per person but what I don't understand is what's the meaning, when it's followed by basis like this statement here.
To compare on a "per capita" basis, means to use "per capita" figures for your comparison. You can similarly say
I will compare the drinks on a "sugar content" basis
This means I will use the sugar content figures to compare the drinks.
The claim is that for "Hotspots" like New York, the (number of tests in New York) ÷ (number of people in New York) is greater than (the number of tests in South Korea) ÷ (The number of people in South Korea). I've no idea if that claim is true.
This compares New York with Korea on a "per capita" basis.