COVID-19 July 11, 2020

I am continuing to overlay a shifted version of the current wave of new infections on top of the original. The rate of increase has been about the same, but unlike the first wave, the current wave is continuing to go up.  The best fit exponential growth curve for the current wave may be showing a very, very slight flattening.  The peak growth rate I saw was about 14.5 days and it is now about 17 days.  That could just be natural variation.

It is also important to note that in the first wave we had very poor testing capabilities and many of the states were lumping presumptive cases together with the confirmed.  Testing capabilities have now improved, although still not to where they need be, and so we should expect to be identifying more cases.  At the same time, many of the states are now counting only confirmed cases.  So, in short, the data from the first wave has a different basis behind it than the current wave.  IIf information was readily available it should be possible to normalize these data to a common standard, but the information isn't readily available and I don't have the time to mess with it.  Just be aware and beware of what you're looking at. Caveat emptor.

COVID-19 July 10, 2020

Still going up.  What else is there to say?  How about wear your mask, save a life?

COVID-19 July 09, 2020

The 7-day average of daily deaths has taken a decisive upward direction.  It seemed almost inescapable that this would happen given the upward trend of new cases, new hospitalizations, and ICU admissions.  It's too early to attach a growth rate to the death trend just yet.  I expect it will have an exponential growth rate, but it's not possible yet to say what that is.  Maybe in about a week.  It certainly seems unlikely to start going back down.  The rate of new infections is continuing its exponential growth and is still at about a 14-day doubling rate.  I did once again have to adjust the y-axis to accommodate the ever-growing numbers.  Seems like that's going to be a regular exercise for the foreseeable future.

COVID-19 July 08, 2020

I was too busy to post yesterday and still too busy today to provide any narrative.  But, here's the data.

COVID-19 July 06, 2020

Way back when, when all this was starting, I cautioned about applying national statistics too broadly.  At the time, New York was surging and the bulk of national statistics were coming from the state.  Those numbers almost swamped out data and trends from other places.  Many states also had growing infections and deaths, but New York was a standout.  If you applied the average national numbers you would get the wrong impression of what was actually happening nationally and you'd get the wrong impression of what was actually going on in New York. 

There's a name for the phenomena that I've described above: Simpson's Paradox.  Wikipedia has a nice summary: https://en.wikipedia.org/wiki/Simpson%27s_paradox .    The bottom line is, be very careful how you interpret statistics.  The statistical number crunching can be accurate, but the interpretation can be deceiving.  You really do need to understand the nature of the problem and some amount of detail about the origin of the numbers.  This goes for most everything: COVID trends, police and race, bias in proposal selection, and bias in college admissions. 

I've previously given some possible explanations for the rapid rise in infections and the lack of such a rise in deaths.  Simpon's paradox is one more possible explanation to add to that list.  Deaths may be decreasing or steady on average across the country, but that is not necessarily the case in Texas, Florida and Califonia the bulk of new cases are coming from.  To my eye, there is at least some indication that the death rate in the first two states has been inching up over the last couple of weeks.  It's not dramatic, and I haven't formally run the numbers, but the trend does appear to be there.  You can look at various other websites that track the data.  Texas deaths look to be going up since mid-June. Same in Florida.  California, however, has been pretty flat. 

And now, I bring you the official numbers from yesterday.  It was a typical down day with the oscillation effect amplified somewhat by the holiday and the weekend.  Let's see the numbers later this week.

COVID-19 July 05, 2020

Today would normally be a down day with the numbers, but given the holiday they look especially wonky.  For example, my state of Colorado reported only 7 new infections where the daily number has been consistently in the hundreds.  I'm guessing people were on holiday and there was no one to answer the mail or to report the numbers.  The cases and deaths are still happening, so we can probably anticipate a bigger bounce later in the week.  Some states, like Florida, reported a record daily number even with the holiday.  That can't be good. 

As reported yesterday, the trends have stabilized.  We are in exponential growth with a doubling time of new cases of about 15 days.  Daily deaths are nearly constant now.  They occasionally go up a bit and down a bit, but on average it's close to a constant rate.

COVID-19 July 04, 2020

Data continues to show that are blowing past what we saw in the first wave.  And, yes, I do believe there was a first wave, contrary to what many are saying.  We are not still in the first wave.  There was a pronounced initial rise, a clear peak, and a gradual but persistent decrease.  That's a wave by most definitions.  It could be said that the first wave brought in the tide that didn't completely recede, but it is a wave nonetheless.  We've now seen a dramatic reversal of trends as the next wave comes in on top of the higher tide.  This is the second wave, and in terms of sheer numbers it is bigger.  Note that the data plotted in green on the new case graph shows the data since June 9 shifted and displayed over the first wave data.  The rate of rise is similar, but we've blown past the peak of the first wave.

Will the second wave be worse than the first?  Hard to say, but it seems likely.  Deaths still have not taken a rapid upward trajectory, but with hospitals and ICUs starting to reach capacity in the hardest hit areas it's hard to see how deaths will not start to increase.  The downward trend has certainly slowed and the 7-day trend has actually shown a slow increase rather than decrease.  See my previous posts over the last few days for additional thoughts about why this is.

Data is plotted below, as usual.  The best fit 7-day line shows just under 50,000 new cases/day.  The exponential fit to the new cases shows a doubling rate of close to 15 days.  This number has, fortunately, more or less stabilized and is no longer rapidly shrinking.  If and when we start to flatten the curve of this wave, we will need to see the doubling rate rise consistently. 

Have a good 4th!  My dog, Layla, thanks you for going easy on the boom booms.

EDIT: I reposted the daily new cases graph b/c I somehow managed to mess up some of the date labels in the original post. Data has not changed.