Characterizing the accuracy of medical tests

As I laid in bed this morning in between waking up and getting up my thoughts drifted to the use of statistics in managing communicable disease in animal farming, specifically related to deciding to quarantine or cull. Typically we do know some kind of accuracy rate for a test for the disease of concern though a separate issue is the degree to which even the medical community act with enough understanding of how that statistic should affect their decisions.

I would like to imagine that we typically know both false positive and false negative rates for tests. However, I realized that, for the decision models I was considering, I also want to know the degree to which each inaccuracy is due to random error or something else, i.e. how much accuracy to the determination would a retest add? For instance, perhaps a false result is because the individual is a little atypical in its biology (baseline levels of this or that) or has some other condition so one would expect the retest to be as misleading as the first.

I am ignorant of both statistics and farm practice. Despite how much industry profit hinges on even small improvements I wonder if perhaps we mostly don't have empirical data on how much it might help to try a retest using a different batch of equipment or whatever or even to what degree false results from one test for a condition correlate with false results from different kinds of test for it. Maybe the tests are often significantly expensive even when compared with the cost of an animal making retests rarely worthwhile.

Rt Hon. Boris Johnson facing questions

In many Western countries we seem to be returning to an age in which we learn how populism fares as it meets reality. On this morning's television while anticipating Dateline London I stumbled onto coverage of the new Prime Minister speaking in Manchester. One thing I liked about the event is that after speaking he took some critical questions from the press. Corresponding to Prime Minister's Questions, back when Boris was Mayor of London it was always interesting to watch him wriggle in the face of Mayor's Question Time. While I would prefer to live in the US I do not by any means regard it as being an improvement in all respects. One thing I find typically missing there is senior politicians facing direct questioning from skeptics.

Update on the small creatures

Local social media claims that the small creatures outside are thrips. I wonder if they feed on and reproduce around the berry plants in the polytunnels that abound locally. Some of the fields don't have polytunnels; perhaps I could take a closer look to try to guess what they grow.