“Scale up” is one of those terms that almost everyone uses and very few people can define. Sure, “scale up” means trying to make some small success much larger—taking a program from neighborhood-scale to country-scale or bigger, for example. But, as it’s used (and over-used) in the development field, “scale up” applies to everything from getting soap to more people through private sellers to replicating a new way to pay teachers, tried in a few demonstration schools, introduced in all government schools.

Sometimes we’re just talking about increasing the amount of spending, and other times “scale up” refers to expanding activities or even impact. Not quite the same thing.

People who talk about scaling up are rarely clear about the path to expanding coverage or impact. Is it through the use of technology, which dramatically reduces the marginal cost of reaching ever-larger populations? Or through the market, where the dynamics of supply and demand drive expanded availability of goods or services? Or through public or non-profit networks, where mandates from the top can, in theory, lead to new practices being rapidly adopted in multiple communities. These are, of course, radically different ways to go from small to big. None of them follows a linear “innovate, prove, scale” path.

But “scale-up” has become a one-size-fits-all phrase, a verbal tic that populates papers and speeches; it’s the thing that motivates all sorts of investments in both new ideas and evaluation: why bother, if not to eventually serve millions? Yet getting from here to there is left in a black box. Truthfully, every time I hear the phrase “going to scale” I wonder if the people talking know themselves what they are trying to say.

That’s why I’ve been intrigued to hear our friends out here in Silicon Valley use their own jargon: “scale up,” “scale out,” and “scale deep.” All refer to the amount and efficiency of data storage, but there’s a special vocabulary that differentiates among different ways to design more storage capacity into computer networks. I wonder if it would help the development field to coin some variants of “scale up” that distinguish what and how more people are being reached. Would it force some conceptual discipline on this sloppy space, or just scale up the use of development jargon?