  There are racial disparities in the COVID-19 test positivity rate, suggesting
that minorities may be under-tested. Here, drawing on the literature on
statistically assessing racial disparities in policing, we 1) illuminate a
statistical flaw, known as infra-marginality, in using the positivity rate as a
metric for assessing racial disparities in under-testing; 2) develop a new type
of Bayesian threshold test to measure disparities in COVID-19 testing and 3)
apply the test to measure racial disparities in testing thresholds in a
real-world COVID-19 dataset.
