[Goose]

Belated information,  the CDC updated their guidelines to stress asymptomatic people should be tested.

To clarify, I think you are referring to testing people who are contacts of a known COVID-19 case. I am not sure this is necessarily a great idea. As I pointed out previously, it depends on the "yield". If the results of such testing so far indicate that the probability of such a person being positive isn't significantly greater than in the general population, it is arguably a wasted test. Does anybody know what the positive rate of such tests has been? I haven't been able to find that information anywhere.

I think "arguably" is stretching things here....

Using SCC numbers. 
Outbreak Associated  1,062  5.9%
Contact to a Case    6,838  38.3%
Travel   33  0.2%
Unknown/Presumed Community Transmission 9,934  55.6%

Using today's 7-day rolling average of 117, there have been about  117*14 = 1638 cases in the last 2 weeks.

For the sake of argument, let's just say there are on average 10 close contacts per case.  Scale it lower or higher, if you wish.
So, of the 1638 cases, there were about 16,380 close contacts.  Of those, roughly 1638 * 0.383 = 627 were found to have COVID-19.
That's 627/16380 = 3.8%

There are about 1.9M (minus 16,380) in the "Haven't been exposed to any of the cases of the last 2 weeks" group.  Out of them during that period, there have been about 1638 * 0.556 = 910 cases.   That's 910/1.9M or a rate of about 0.05%.

3.8% >> 0.05%

Testing of known contacts seems likely to find more cases than testing of the general populace.   I don't have any numbers of asymptomatic vs symptomatic ratios in known contacts vs general populace, but I'd think if anything, an asymptomatic contact is even more likely to test positive over an asymptomatic non-contact.

The problem with the above analysis is timing. The SCC number of positives who were contacts to a case includes all contacts who tested positive at any time. They may have been tested initially and been negative, and then a week/a day later felt ill and got tested. The idea that testing people who are known to have been exposed should result in more positives is reasonable. However, it may be that if you test "immediately", they aren't sick yet. Unless you have THAT number, you don't know how effective immediate testing is. It may be that almost nobody who is asymptomatic tests positive when tested "immediately". Perhaps it is better to wait a few days. I don't know the answer, but unfortunately the "contacts to a case" number doesn't tell us.

[Goose]

Belated information,  the CDC updated their guidelines to stress asymptomatic people should be tested.

To clarify, I think you are referring to testing people who are contacts of a known COVID-19 case. I am not sure this is necessarily a great idea. As I pointed out previously, it depends on the "yield". If the results of such testing so far indicate that the probability of such a person being positive isn't significantly greater than in the general population, it is arguably a wasted test. Does anybody know what the positive rate of such tests has been? I haven't been able to find that information anywhere.

I think "arguably" is stretching things here....

Using SCC numbers. 
Outbreak Associated  1,062  5.9%
Contact to a Case    6,838  38.3%
Travel   33  0.2%
Unknown/Presumed Community Transmission 9,934  55.6%

Using today's 7-day rolling average of 117, there have been about  117*14 = 1638 cases in the last 2 weeks.

For the sake of argument, let's just say there are on average 10 close contacts per case.  Scale it lower or higher, if you wish.
So, of the 1638 cases, there were about 16,380 close contacts.  Of those, roughly 1638 * 0.383 = 627 were found to have COVID-19.
That's 627/16380 = 3.8%

There are about 1.9M (minus 16,380) in the "Haven't been exposed to any of the cases of the last 2 weeks" group.  Out of them during that period, there have been about 1638 * 0.556 = 910 cases.   That's 910/1.9M or a rate of about 0.05%.

3.8% >> 0.05%

Testing of known contacts seems likely to find more cases than testing of the general populace.   I don't have any numbers of asymptomatic vs symptomatic ratios in known contacts vs general populace, but I'd think if anything, an asymptomatic contact is even more likely to test positive over an asymptomatic non-contact.

The problem with the above analysis is timing. The SCC number of positives who were contacts to a case includes all contacts who tested positive at any time. They may have been tested initially and been negative, and then a week/a day later felt ill and got tested. The idea that testing people who are known to have been exposed should result in more positives is reasonable. However, it may be that if you test "immediately", they aren't sick yet. Unless you have THAT number, you don't know how effective immediate testing is. It may be that almost nobody who is asymptomatic tests positive when tested "immediately". Perhaps it is better to wait a few days. I don't know the answer, but unfortunately the "contacts to a case" number doesn't tell us.