Re: CDC Officials Warn of Coronavirus Outbreaks in the United States.
Slate: Georgia’s Reopening Depended on Missing Data: There’s a lag between when COVID-19 is found and when we know about it.
There are several reasons the epidemic may appear to be declining, even when cases are steady. First, there are delays between testing and reporting due to the time it takes to transport samples and backlogs in analysis, and then the time it takes to record and report those tests to the state. Second, confirmed COVID-19 cases are assigned to the date the test was performed, not the date when the results come back, which could be days to several weeks later. This means that numbers will constantly be retroactively adjusted. And while this may be acceptable practice in the context of intervention efforts, if we don’t acknowledge and account for the delay, it will provide a faulty barometer to those who want to use recent case reports as a real-time measure of the epidemic trajectory.
One of the criteria in the “Opening Up America Again” guidelines issued by the White House stipulates that cases should be on a downward trajectory over a 14-day period. But this 14-day period is precisely when case numbers are underreported. The infographic shows that while new cases appeared to be falling between April 15 and April 29 when viewed on April 29, in hindsight, new reported cases were at similar levels in late April as in early April. Notably, the highest recorded number of new cases up to that point was recorded on April 27, days before reopening. It was not clear at the time it was announced that Georgia met the conditions for reopening. Today we know those conditions were not met.
Slate: Georgia’s Reopening Depended on Missing Data: There’s a lag between when COVID-19 is found and when we know about it.
There are several reasons the epidemic may appear to be declining, even when cases are steady. First, there are delays between testing and reporting due to the time it takes to transport samples and backlogs in analysis, and then the time it takes to record and report those tests to the state. Second, confirmed COVID-19 cases are assigned to the date the test was performed, not the date when the results come back, which could be days to several weeks later. This means that numbers will constantly be retroactively adjusted. And while this may be acceptable practice in the context of intervention efforts, if we don’t acknowledge and account for the delay, it will provide a faulty barometer to those who want to use recent case reports as a real-time measure of the epidemic trajectory.
One of the criteria in the “Opening Up America Again” guidelines issued by the White House stipulates that cases should be on a downward trajectory over a 14-day period. But this 14-day period is precisely when case numbers are underreported. The infographic shows that while new cases appeared to be falling between April 15 and April 29 when viewed on April 29, in hindsight, new reported cases were at similar levels in late April as in early April. Notably, the highest recorded number of new cases up to that point was recorded on April 27, days before reopening. It was not clear at the time it was announced that Georgia met the conditions for reopening. Today we know those conditions were not met.
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