When the monthly jobs report comes out Friday, many eyes will undoubtedly shoot to the unemployment rate. But that number alone doesn’t tell the whole story.

“It’s gotten harder [to figure the unemployment rate] because Americans have become less willing to respond to surveys of all kinds,” says David Leonhardt, columnist and editor of the Upshot at the New York Times.

A large part of that, Leonhardt says, is our changing behavior when it comes to answering our phones.

“Think back to 1975 — you’re sitting at home, your phone rings, you have no idea who it is, you pick it up, it’s a pollster, you’re willing to answer it,” he says. “Today, you’ve got your cell phone, you don’t even have a landline, it may be harder for the poll firms to figure out where you are and thus [how] to reach you. But it’s also a case of, you see ‘888’ pop up and you think to yourself, ‘I’m not answering that.'”

It’s a reminder, Leonhardt says, that the unemployment numbers aren’t the be-all, end-all of economic data.

“I would encourage some people to take the attention that now goes to the unemployment rate and shift it to job growth, which actually comes from a larger survey of businesses, or look at the number of Americans who are employed, which captures this phenomenon of discouraged workers,” Leonhardt says.