For more than two months now, the phrase “flatten the curve” has been ubiquitous. Most people have only a vague idea of what it means. But for the sake of a sensible discussion of public health issues, it may be well to understand that its meaning is pretty specific, and it isn’t just “avoid the virus”!
Imagine a typical “bell curve,” a curve of the statistical distribution of random outcomes where the most likely outcome is in the middle of a range. You have surely seen such curves. Now: imagine two variants: first a variant in which the “bell” is tall and narrow. There is a swift movement up to the norm and a swift movement down again, with a short range of possibilities. Lastly, consider the opposite, a variant in which the “bell” is short and broad. The norm is not markedly different from the quantities just to the left or the right of it.
Scientists model epidemics, or the various “surges” of multi-wave epidemics, as bell curves in which the X (left-to-right) axis represents the passage of time, the y (up-down) axis represents the new infections per day, and the top or “norm” of the bell represents the peak of the epidemic, the day when frequency of infection turns, blessedly, down.
The point to remember is that in its technical significance, “flattening the curve” urges a course of conduct that may prolong the duration of epidemic, and may not have any effect on the total number of cases. Imagine a hand pressing down on the norm of a spiky bell, making it a short and broad bell instead.
In Pill Form:
Why would the visible hand of public health authorities want to do that? Because the high point of an epidemic may take cases far above the number of beds and other resources available in a city’s or region’s hospitals. If an epidemic overwhelms hospital facilities, even if only for a short period, so that patients (both sufferers from the epidemic and others whose maladies simply have unfortunate timing) stuck perhaps on gurneys in the corridors, will have worse outcomes, often fatal outcomes, that could otherwise have been avoided. Flattening the curve means reducing the worst of it below the point where the line-up of gurneys in corridors would become necessary. So even if there are just as many cases and the epidemic is a felt fact for longer, fatalities will be fewer in the “flattened” case. That is what the phrase calls for.