COVID Archives

What will college testing do to the data?

Nationally, we’re still seeing a consistent and steady decline in known active cases. Over the last 6 days, we’ve dropped an average of just over 9,000 active cases per day. Florida, Arizona, Colorado, and South Carolina have been dropping particularly fast, but lately we’ve seen a lot of improvement in California as well. At this rate, I expect us to be down to April known active case levels by mid-September.

We have nearly 20 million college students returning to school from mid-August to Labor Day, and many schools are implementing universal testing for COVID. I don’t know what percentage of students will be tested, but I’m expecting to see a rise in cases over the next week as these tests are reported, and then a decline the week after. I’ve had reports from some schools in the sub 1% positivity rate – if any of you have information about various school stats please send them to me. We have very little data on entire sub-populations being tested, so this is a rare chance to learn more about total prevalence. In any event, the college populations being tested have a very low average age (even with faculty and staff in the mix), so these cases will have a negligible impact on the daily death count, since college age people have a near zero mortality rate.

I’ve been talking a lot about herd immunity, and how a significant population level of innate resistance to COVID would explain the data we’re seeing. I’m no expert in disease, but I’ve latched on to this idea because it’s the only explanation on the table for why this disease peaks at such low numbers. Here is a piece from Bloomberg news last week, which talks about scientists rethinking herd immunity based on T-Cell cross reactivity with the common cold. Yes, it IS an opinion piece, but it checks a lot of boxes for me and I thought you might find it interesting.

In other news, the IHME model updated today. They are projecting deaths along 3 scenarios out to December 1st: universal masks, current projection, and all mandates easing. You can see it here:

FYI, I pinned last Sunday’s discussion of Sweden’s results to the bottom of this report.

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: 756,105 (very high)
  • Total Pending tests reported today: 4,199 (extremely low)
  • National reported case Growth Rate today: 0.85% (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 about 155,000 known active cases since the peak of July 23rd. That’s a 33% decline, and puts us back where we were in early July. I expect to see a rise over the next week of perhaps 25,000 cases, as the wave of college-based tests moves through the data. However, I think that bubble is all over by the week after. I hope I’m wrong on the first part and right on the second.

Look at the daily new cases. We’re looking at a broad pattern of decline since mid-July.

The daily death count is flat for about a month now. I expect a gradual decline beginning this coming week. 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 4 – 5 times higher. If we get a lot of college driven tests in the coming week, this number will decline.

On to the states.

Here is Arizona, now down 80% from the peak just 6 weeks ago. To put this in perspective, I model that Arizona now has less COVID than Virginia.

SC also continues to improve. SC is now down 59% 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 strong recovery story. Interestingly, I noticed Miami flattening first, but Miami is not declining as fast as the rest of the state. Florida is now down an amazing 64% from the top.

Now, California – what a difference a week makes. California has dropped 27% in 6 days! However, since California peaked at only 0.18% of the population, I’m thinking there is more to come here. On the other hand, Sweden peaked at a much lower percentage, as they had a quite high prevalence to reported ratio. That could be happening here. As always, I need to report that California is one of the states that counts tests rather than people.

Georgia’s recovery is accelerating lately. Georgia hit a high of 0.25% of the population, so I’m thinking that they did peak on July 24th. GA is now down 32% 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 also a slower recovery than 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 been steadily declining for over a month, but now is up for the past 4 days. I’m hoping this is an anomaly, or perhaps a result of college testing, as NC schools start very early.

Here is the daily death report for NC, flat for nearly a month now. I’m expecting this to begin a definitive decline this week, based on the drop in daily new case count.

And here is the daily new case count for NC. A noticeable drop from the peak in mid-July.

Washington is now down 41% from the peak on July 19th. I’m skeptical about this, as the high water mark you see here is at just 0.087% of the population. However, that peak is now over a month old, so that’s hopeful.

Here are NY and NJ – hard to see since the numbers are small, but NJ has had quite a drop lately, down to about 1,600 cases.

Here is Massachusetts. That bump you see on August 19th is a result of a new procedure in Massachusetts for reporting “probable” cases. Here is the quote from The COVID Tracking Project:

“On August 12, MA began reporting probable cases weekly, not daily. This can lead to apparent spikes in the data when the weekly numbers are incorporated, as happened on August 19.”

So it looks like we’ll see a little spike of probably cases every Wednesday.

…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. Big drop in the past few days, though.

PA has been dropping for 3 weeks. 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 3 weeks. Colorado has declined 53% over this time period, and is now down to 2,000 known active cases. Very small numbers here.

So that’s it for today. I’ll report again in a few days.

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.