Sometimes, you think that you found something interesting but the Maryland Department of Health is already presenting it on its COVID-19 dashboard 😀

For instance, I calculated the percentage of residents of the different counties ever tested (regardless of the test result). I found out that a third of Maryland counties (8/24) tested at least once more than 25% of their residents. Indeed, as of yesterday (August 10), here are the counties in that category:

County (alphabetical order)	% population ever tested
Baltimore	25.8%
Baltimore City	30.2%
Dorchester	30.4%
Kent	30.6%
Somerset	30.8%
Talbot	28.6%
Washington	27.7%
Wicomico	25%

While we are at it, here are the 5 counties with less than 20% of their population tested (still as of August 10, 2020):

County (alphabetical order)	% of population ever tested
Calvert	14.9%
Cecil	15.3%
Charles	18.6%
Harford	18.1%
Queen Anne’s	19.4%

Graphically, we see that all counties are testing more and more, and increasing at approximately the same speed:

As you can see, there are 2 minor issues with the dataset from the MDH API. First, Somerset reported more than double the normal number of tests on June 18, 2020; it went back to “normal” on the next day (I suspect an encoding error here, see highlight below). Then, there is no data after July 7; data resumes on July 13 (a posteriori, I don’t recall reading any issue about county data collection during that time). None of these prevents looking at the current data.

Now, as I mentioned, the official dashboard has already this data, presented by quartile, as a kind of competition between counties 😉 … (the % are slightly different, probably because we are using different sources for the population totals – I’m using the population projections from the Maryland Department of Planning).

To be continued …

As usual, you’ll find other graphs on my page about COVID-19 in Maryland (and figures above are updated with new data as they appear) and the data, code and figures are on Github (including these ones).