COVID Archives

Looks like minimal impact from college testing so far…

When I reported last week, I was expecting a bump in active cases this week from the ubiquitous testing at universities as the semester begins. So far, however, we’re not seeing it. Not only has the case count not risen, there is no spike in testing volume. Some schools are doing universal testing, some are testing all students moving into dorms, and some are only testing symptomatic students. Some schools are reporting tests and positives each day, and some (Like Arizona State University) aren’t reporting any data. I did a quick search earlier this week and found snippets of data – I combined this with reports sent to me by readers of this report, and have this:

This is VERY unscientific – just a few that come up on a quick google search – but the numbers are smaller than I was expecting. I’m modeling known active cases in the United States right now at 289,000, or about 0.09% of the population. If we hit that with a prevalence to known case ratio of 10, we get 0.9%. I was expecting college students to be higher than this, given their elevated socializing. However, the numbers in this admittedly ragtag data set is smaller than that. I wish I had 25 researchers – we could learn a great deal digging into the college testing. We’ll just have to watch and see what happens. In any event, if we have a positive rate of 0.5%, that would still be 100,000 extra cases across the 20 million college students in the U.S. Of course, I believe most universities are not testing the entire student body – they can’t be – we’re not seeing that kind of lift in total tests reported. In any event, an increase in college age cases will have a negligible impact on the daily death count, since people that age have a near zero mortality rate from the disease.

I’ve been writing about targeted, rather than blanket, restrictions on social mobility since I did my first mortality calculations in April. I’ve long thought that the correct public policy would be to protect those demographic groups with the highest COVID mortality rates, but let working age people continue to participate in the economy. I think this is likely what is happening naturally, and now it is making its way into the mainstream. Here is a good article from Monday’s Wall St. Journal:

Feel free to send me your questions about my assumptions, methodology, or modeling in general.

  • Likely date of active case peak (Chalke modeling): July 23
  • Likely date of peak deaths (IHME): April 16 (last revision on August 21)
  • Total Test Results reported today: 742,340 (very high)
  • Total Pending tests reported today: 11,168 (low)
  • National reported case Growth Rate today: 0.76% (very low)

Shane Chalke Interviews


Groom Ventures has agreed to host a website that will archive my daily reports, and supplement with other commentary. John Groom worked at one of my companies back in the day, and is an excellent writer. The website is: For those of you that post my daily report on Facebook, let me suggest you link to this site, as the direct Facebook posts don’t seem to copy the graphs.

Daily Analysis

Here is the national picture. We’ve dropped over 179,000 known active cases since the peak of July 23rd. That’s a 38% decline, and puts us back where we were in late June. I was expecting a rise this week as the wave of college-based tests moves through the data, but we’re not seeing it yet. Perhaps over the next week as students in the northeast make their way back to campus, but so far, we don’t even have a bump in testing volume – that’s curious to me.

Look at the daily new cases. We’re looking at a steady and welcome decline since mid-July.

The daily death count is flat for about a month now, with an inkling of decline over the past two weeks. Here is the picture:

Here are the daily deaths per 1,000 known active cases. This disease is far less deadly than it was in April, when deaths per active case were far higher. The gradual rise is a result of daily deaths lagging the dropping case count by 2-3 weeks.

On to the states.

Here is Arizona, now down 86% from the peak just 7 weeks ago. I’m modeling that Arizona has less than 4,000 known active cases left.

SC is also looking far better than a month ago. SC is now down 61% from the peak. Note that South Carolina double counts cases, as they treat each positive test as a new case (per The COVID Tracking Project).

Here is Florida – another very rapid recovery. There is still a lot of COVID in Florida (I model over 23,000 known active cases), but far less than the 83,000 cases at the peak. Florida is now down an amazing 72% from the top.

Here is California – now down 44% from the peak, and back where they were in late June. I’m still not confident there won’t be more localized peaks here, with California maxing out at only 0.18% of the population. As always, I need to report that California is one of the states that counts tests rather than people.

Georgia continues to make progress. Georgia hit a high of 0.25% of the population, so I’m thinking that this is it. GA is now down 37% from the peak. Note here again, the case numbers are exaggerated. Georgia counts each positive test as a case (according to The COVID Tracking Project).

Texas is now down 49% from the peak about a month ago. Not as smooth or dramatic a recovery as Florida or Arizona. Note that Texas also reports positive tests as cases, so is doing some level of double counting (per The COVID Tracking Project).

NC has had a pronounced rise over the past week (over 2,000 cases), but it looks like we’re past that bubble now, as the daily case count has been falling for 6 days (except for today). Based on that, I expect this to turn around over the next few days. Virginia shows a sharp drop today, but that’s because they didn’t report numbers today (this happens once in a while in VA). VA will pop back up tomorrow.

Here is the daily death report for NC, flat for a month, and now showing early signs of decline.

And here is the daily new case count for NC. A noticeable drop from the peak in mid-July, and then 2 or 3 data points above the trend line over the past week. I’m thinking that this could be college testing, as NC schools start so early in the year, but I don’t know.

The COVID Tracking Project just did a major revision of Washington data, placing cases back on the proper dates. We now see a new picture of Washington which looks much better. This is a 79% decline from the peak. With the messy data last week, we showed a much smaller 41% decline. This is a great illustration of how newly discovered historical cases reported as new can skew the data, making things look much worse than they are.

Here are NY and NJ – I think the interesting observation here is that even though both states peaked very early and recovered rapidly, they don’t seem to make much progress once cases get to a low level. It seems asymptotic. It makes me wonder if the course of this disease is to simmer indefinitely at low levels.

Here is Massachusetts. Similar to NY and NJ, it continues to simmer along in a stationary fashion. There are few active cases, but as fast as they recover, an equal number of new cases are reported.

…And here is Michigan. Michigan peaked at a very low 0.089% of the population, so may continue to grow if my theory is correct. Nonetheless, MI has been relatively flat for a month now.

PA has been dropping steadily for 4 weeks not. However, I believe PA has more growth to come, as the peak was very low (0.091% of the population).

And finally, here is Colorado. A sharp drop over the past month. Colorado has declined about 50% over this time period, and is now down to about 2,000 known active cases. Very small numbers here.

So that’s it for today. I’ll report again on Monday or Tuesday.

The numbers are still very small as a percentage of the population. Unless you’re in a high density area, your chances of contracting COVID are very small. However, even though the probability is very small, that doesn’t help if you’re the one catching it. Everyone please continue to be as cautious as you feel necessary.

–Shane Chalke, FSA

Leave a Reply

Your email address will not be published. Required fields are marked *