“I think it’s key not to get fixated on the exact numbers,” Dominique Heinke, an epidemiologist in Massachusetts, told Vox. “You can look at a range of models and say, ‘We can expect it to be at least this bad.’ ”

If predictions change as more data becomes available, that doesn’t mean a model was “wrong.” That just means researchers have better information about the virus.

And by showing a worst-case scenario, models can motivate people to act.

“Unlike the weather … we actually influence the outcome,” Caitlin Rivers, a professor at the Johns Hopkins Center for Health Security, told Vox. “So people see the numbers, and they are motivated then to be more aware, stay home and using good hygiene and doing all the things that really change that outcome.”