Déjà Vu All Over Again
After a long stretch of virtually no new cases in Douglas County, the County is experiencing a discouraging increase in the number of new cases per day, just as the country deals with crushing increases in most of her states. This is not a second wave. As Anthony Fauci put it, the United States is “still knee deep in the first wave.”
But let’s stick with Douglas County. The OFFICIAL WEBSITE for the County provides an archive of press releases from the Douglas County COVID-19 Response Team. Each press release discloses the number of new cases for the day, the total number of cases so far (both confirmed and presumptive), and the number of negative test results (which demonstrates that the positive test rate is very low indeed at about 1%). But those data points—when eyeballed one point at a time—do not tell a very compelling story. To see the trends of the pandemic in our neck of the woods (or any neck, for that matter), we need to visualize the data, which is a fancy way of saying graph it.
Nationwide data reveals that the level of transmission in the United States never dropped low enough (or long enough) to declare that the first wave has ended. Instead, we have experienced two surges within the first wave. The graph below shows a line of data points for Douglas County—specifically, the number of cases in the County over time. The graph is composed of three main parts of interest: two surges and a plateau.
The first surge occurred early as the virus was introduced to and spread across a bewildered nation.
A plateau followed, during which people became more careless, defiant, and complacent.
Finally, a second surge emerged in June.
Note that the shape of the cumulative graph for Douglas County looks very like the graph of new cases per day for the United States, which also presents a second surge following the premature opening of businesses in the Sun Belt (including California).
Why does this graph tell a compelling story? The story line—also called a trend line—includes two plot points that convey not only what has happened and is happening but also what will likely happen (a solemn repeat of history). The key to understanding this trend is slope (steepness).
Imagine slope as the tilt of a surface. Your kitchen floor has no slope. A boat ramp has a slope of about 8 degrees. A wall has the ultimate slope of 90 degrees. The higher the slope, the faster we are adding cases to our COVID curve and the more alarmed we should be. In the case of Douglas County, the first surge had a slope of about 56 degrees. The current (second) surge has a slope of about 65 degrees. This one line is packed with the only signs and omens you need to conclude that businesses were opened too soon, that too many people are not following CDC guidelines, and that now is the time to make decisions based on science and the consensus of the medical community.