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The Daily COVID-19 Picture

From upper left: The chart of daily COVID-19 makes trends difficult to see, because it continually leaps up and down, depending on the day of the week.

Chart 1 - Daily Case Raw Data

Chart 1 counts the days since March 1 on the x axis, and total daily cases on the y axis.

As soon as the weekend comes around, the throughput of testing centers and lab processing takes a dip. This jagged line is very hard to read. The behaviors and choices of people who need tests, of medical facilities, and of reporting institutions changes from day to day, with especially big differences when there are days off for weekends or holidays.

It therefore never makes sense to compare a Sunday to the previous Friday - there is always a big drop.

Instead, compare each weekday only to the previous same day of the week. Don't ask whether this Sunday is lower than Saturday; ask whether this Sunday is lower than last Sunday.

Chart 2 - Weekdays Raw Data

Chart 2 counts the number of weeks since March 1 on the x axis, the number of daily cases for each weekday on separate lines.

As we would expect, they follow a roughly similar profile, but at different levels. For any given week, the spread between different days of the week is considerable. In order to try and spot the current trend, we need to ask whether how each weekday's number stands in relation to that same weekday's other numbers. The *worst* Sunday ever would be expected to occur close to the worst Saturday ever, the worst Monday ever, and so forth. In order to scale these different days of the week in a meaningful and informative way, Chart 3 scales each weekday to a percentage between 0 and 1. The 1 is for 100% - in that week, that weekday reached its highest point ever observed during the pandemic. The other numbers are fractions of that peak, for that same weekday.

Chart 3 still has weeks since March 1 on the x axis, and different lines for each weekday, BUT shows each weekday's fraction of that weekday's peak on the y-axis.

Chart 3 - Weekdays Scaled Data

We can see that this produces a much tighter grouping, which is the result of comparing apples to apples and oranges to oranges, instead of throwing them all in together. As of this analysis on Nov 23, despite the recent weekend we find no discernible moderating trend in the Weekdays Scaled Data. The COVID-19 pandemic in the USA continues to climb at a steep rate. Unfortunately, the value of '1', for 100%, on this chart, falls on the week this chart was made, indicating that the most recent week of the pandemic contains the highest numbers ever observed in the USA. [Ignore Daily Scaled Data here. This chart maps each single day compared to the highest day ever observed, for a number between 0 and 1.]

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