Stats Hold a Surprise: Lockdowns May Have Had Little Effect on COVID-19 Spread

In 1932, Supreme Court justice Louis Brandeis famously called the states “laboratories of democracy.” Different states can test out different policies, and they can learn from each other. That proved true in 2020. Governors in different states responded to the COVID-19 pandemic at different times and in different ways. Some states, such as California, ordered sweeping shutdowns. Others, such as Florida, took a more targeted approach. Still others, such as South Dakota, dispensed information but had no lockdowns at all.

As a result, we can now compare outcomes in different states, to test the question no one wants to ask: Did the lockdowns make a difference?

If lockdowns really altered the course of this pandemic, then coronavirus case counts should have clearly dropped whenever and wherever lockdowns took place. The effect should have been obvious, though with a time lag. It takes time for new coronavirus infections to be officially counted, so we would expect the numbers to plummet as soon as the waiting time was over.

How long? New infections should drop on day one and be noticed about ten or eleven days from the beginning of the lockdown. By day six, the number of people with first symptoms of infection should plummet (six days is the average time for symptoms to appear). By day nine or ten, far fewer people would be heading to doctors with worsening symptoms. If COVID-19 tests were performed right away, we would expect the positives to drop clearly on day ten or eleven (assuming quick turnarounds on tests).

To judge from the evidence, the answer is clear: Mandated lockdowns had little effect on the spread of the coronavirus. The charts below show the daily case curves for the United States as a whole and for thirteen U.S. states. As in almost every country, we consistently see a steep climb as the virus spreads, followed by a transition (marked by the gray circles) to a flatter curve. At some point, the curves always slope downward, though this wasn’t obvious for all states until the summer.