Something potentially momentous is happening inside startups, and it’s a practice that many of their established competitors may be forced to copy if they wish to survive. Firms are keeping head counts low, and even eliminating management positions, by replacing them with something you wouldn’t immediately think of as a drop-in substitute for leaders and decision-makers: data.

“Every time people come to me and ask for new bodies it turns out so much of that can be answered by asking the right questions of our data and getting that in front of the decision-makers,” says James Reinhart, CEO of online secondhand clothing store thredUP. “I think frankly it’s eliminated four to five people who would [otherwise] pull data and crunch it,” he adds.

The story is the same at dozens of other startups, says Frank Bien, CEO of Looker, a company that offers a cloud-based service for turning a company’s data into dashboards that anyone in the firm can use. Across numerous interviews with other startups, as well as Looker competitor RJMetrics, I heard the same themes again and again: Startups are nimbler than they have ever been, thanks to a fundamentally different management structure, one that pushes decision-making out to the periphery of the organization, to the people actually tasked with carrying out the daily business of the company. And what makes this relatively flat hierarchy possible is that front-line workers have essentially unlimited access to data that used to be difficult to obtain, or required more senior managers to interpret.

In the past, says Mr. Bien, companies were beset by “data bread lines,” in which managers had all the data they needed, but their staffers had to get in line to get the information they needed to make decisions. In the world of just a few years ago, in which databases were massively expensive and “business intelligence” software cost millions of dollars and could take months to install, it made sense to limit access to these services to managers. But no more.

Chubbies, a clothing startup that has achieved rapid growth by narrowly targeting college fraternities, is practically built on this devolution of power to its employees. Chubbies doesn’t even have a CEO; instead, it has four co-CEOs, charged with maintaining a “church of quadfecta of management excellence,” says Tom Montgomery, one of the four. Every co-CEO is in charge of his own business function, a structure that is repeated, fractal-like, all the way down the company’s hierarchy.