In the fog of pandemic, every statistic tells a story, but no one statistic tells the whole truth. Conservatives seeking refuge in today’s death counts may find, in a matter of days, that deaths are clearly resurging and their narrative is rapidly deteriorating. But liberals, too, should avoid the temptation to flatly reject any remotely positive finding, for fear that it will give succor to the president.
What follows are five possible explanations for the case-death gap. Take them as complementary, rather than competing, theories.
1. Deaths lag cases—and that might explain almost everything.
You can’t have a serious discussion about case and death numbers without noting that people die of diseases after they get sick. It follows that there should be a lag between a surge in cases and a surge in deaths. More subtly, there can also be a lag between the date a person dies and the date the death certificate is issued, and another lag before that death is reported to the state and the federal government. As this chart from the COVID Tracking Project shows, the official reporting of a COVID-19 death can lag COVID-19 exposure by up to a month. This suggests that the surge in deaths is coming.
In Arizona, Florida, and Texas, the death surge is already happening. Since June 7, the seven-day average of deaths in those hot-spot states has increased 69 percent, according to the COVID Tracking Project.
The death lag is probably the most important thing to understand in evaluating the case-death gap. But it doesn’t explain everything. Even where deaths are rising, corresponding cases are rising notably faster.
2. Expanded testing is finding more cases, milder cases, and earlier cases.
There is a bad way to talk about testing, and a nuanced way to talk about it.
The simplistic version, which we often hear from the president, is that cases are surging only because the number of tests is rising. That’s just wrong. Since the beginning of June, the share of COVID-19 tests that have come back positive has increased from 4.5 percent to 8 percent. Hospitalizations are skyrocketing across the South and West. Those are clear signs of an underlying outbreak.
Something subtler is happening. The huge increase in testing is an unalloyed good, but it might be tricking us with some confusing weeks of data.
In March and April, tests were scarce, and medical providers had to ration tests for the sickest patients. Now that testing has expanded into communities across the U.S., the results might be picking up milder, or even asymptomatic, cases of COVID-19.
The whole point of testing is to find cases, trace the patients’ close contacts, and isolate the sick. But our superior testing capacity makes it difficult to do apples-to-apples comparisons with the initial surge; it’s like trying to compare the height of two mountains when one of the peaks is obscured by clouds. The epidemiologist Ellie Murray has also cautioned that identifying new fatal cases of COVID-19 earlier in the victims’ disease process could mean a longer lag between detection and death. This phenomenon, known as “lead time bias,” might be telling us that a big death surge is coming.