Covid tests in Texas The second entry to look at the testing in Texas. This time there is much more data to examine, but also a new and irritating problem. At some point, for some counties, antibody testing got mixed in with the PCR tests, so the numbers are not nearly as good as they should be. Last I read, about 10% of the tests are the wrong test, but I suspect this is not evenly distributed by county, but rather concentrated in a few.
Introduction Towards the end of May the state of Texas suddenly began adding the number of COVID-19 cases detected amongst prison inmates to the county totals for the counties in which the prisons resided. However, they have not indicated if they did this change on a single day, or if it may have taken place over several days, for different prisons. In this bit of work, I will try to ferret out what they did as best I can, so that I may best correct my own data.
Piecewise data fitting As the COVID-19 pandemic progresses, the simple exponential and logistic models no longer fit the data very well. As waves of infection and retrenchment occur, it seems likely that the best fits will be done piecewise. For this blog entry I will experiment with various schemes to see if I can get a reasonably good strategy for constrained fitting to the data. As I have a well-structured dataset for all the counties in Texas, that is what I will use for the experiments.
Miscellaneous analyses related to the Covid-19 pandemic After reading the paper this morning about a county nearby (Houston county) with zero reported cases, I got curious. What does the distribution of test coverage look like, i.e., number of tests per capita? And also, what is the rate of tests that come back positive? So let’s look at the data. We can now grab an excel spreadsheet from the state that gives number of tests per county.