It's a small sample, but it's a comprehensive one as everyone was tested. On the Diamond Pricess, it only reached 20% of the people on board, and of those 60% had no medical symptoms. Overall 1% of people catching it died.
As a cruise ship the passengers tend to be older, but the crew tend to be younger.
Doesn't matter if you test 1 million people or 10,000 people, if you aren't doing statistically significant tests, it's meaningless to draw conclusions.
If physical distancing is successful in reducing the reproduction number (R0), you will then want to track, trace and isolate every case to prevent further outbreaks when you relax the rules.
"better understanding of the virus' properties, like the distribution of symptoms, severities, and mortality rate"
Random and self-selecting testing doesn't seem to offer much in that. Imagine going to a Nics game and asking everyone there who they support, chances are you'll get a lot of Nics fans.
How does that give you a better indication of mortality rate or severity if you have no idea how many people actually have it, because you only have a statistically insignificant tests.
Sure, if you're in the stage where you want to lock down specific people (like South Korea) then random widespread testing works to increase the number of locked down people.
But if you're in a country where you've locked down everyone already, then testing could well be increasing the risk.
If the population assumes they've tested positive, and acts like they are, then what does testing add?
> If the population assumes they've tested positive, and acts like they are
That is a fair point, and I agree that testing is most important when there are a limited number of cases - a stage which was essentially missed by Western governments but hopefully will have another opportunity.
I don't agree that populations are acting like they have tested positive, though, or can do that en masse.
If you know yourself to be positive, you should ideally be taking stricter measures - like having people leaving food at your doorstep.
Only people who are not infectious should be involved in food and resource distribution.
In order to enact that, you would need to actually test.
The purpose of random testing or testing of more people who have exposure but no symptoms would be to limit household spread by separating people from their households or having the households act differently knowing that they'll be constantly exposed.
As a cruise ship the passengers tend to be older, but the crew tend to be younger.
Doesn't matter if you test 1 million people or 10,000 people, if you aren't doing statistically significant tests, it's meaningless to draw conclusions.