Many places need ~10 PCR tests to find one infection while the group tested is often highly pre-selected, such as “symptomatic people with known contacts”. You should have much higher prior it is infected. Some of the numbers proposed in the “tip of the iceberg” framework would actually mean the prior probability of being infected in the “tested group” is lower than in the general population.
With this hypothesis its very hard to make sense of China. Outside of Hubei, China managed to contain the outbreak in large part by contact tracing & testing. However if you assume there is some very high number of cases you don’t know about, it is difficult to explain why contact tracing can influence anything.
Of the many problems of this theory...
Many places need ~10 PCR tests to find one infection while the group tested is often highly pre-selected, such as “symptomatic people with known contacts”. You should have much higher prior it is infected. Some of the numbers proposed in the “tip of the iceberg” framework would actually mean the prior probability of being infected in the “tested group” is lower than in the general population.
With this hypothesis its very hard to make sense of China. Outside of Hubei, China managed to contain the outbreak in large part by contact tracing & testing. However if you assume there is some very high number of cases you don’t know about, it is difficult to explain why contact tracing can influence anything.