When the Academy of Motion Picture Arts and Sciences reveals its list of new invitees next month, shrewd observers will have an eye on the documentary branch.

Lately, attention has fallen mostly on race and gender, as the Academy scrambles to reach its goal of doubling female and ethnic minority membership by 2020.  But another deeply consequential shift has affected the group in recent years: That is, the relative weight of its 17 branches has been changing. And none has proven more robust than the doc branch, which has rapidly expanded, even as branches housing directors, writers, actors, publicists and such have grown far more slowly, or even diminished.

Rumblings within the Academy say the documentary branch is poised to expand again when the group extends its next wave of invitations, following a Board of Governors meeting set for June 27.

At present, around 277 filmmakers belong to the branch, which makes it smaller by far than the acting or producing branches, but larger than those representing casting directors, cinematographers or costume designers, for instance. In all, the Academy has around 6,700 voting members, so documentarians represent roughly 4 percent of the whole.

What’s striking, though, is that the documentary group has been growing at a rapid clip. Last year, it expanded by about 17 percent. That was slightly less than the growth rate in the directors branch, which was up by 20 percent to more than 470 members. But the directors to some extent were making up for slower growth in preceding years. Since 2012, based on figures provided by the Academy’s Margaret Herrick library, the documentary branch has grown by about 59 percent, while the directing branch is up by less than half as much, about 27 percent, for the period. In the same years, the number of writer-members grew about 7.7 percent, while producers grew 9.1 percent, publicists were up 4.9 percent, and actors fell by almost 2 percent, to around 1,160.

The documentary tribe is surging. Actors are slipping back. This might represent a bow toward digital filmmaking, fresh interest in the documentary form, or make-good for severe under-representation in the past. Or it may be that documentarians—who include many around the world with small crews, tiny budgets and big ideas—are a ready pool for the sort of diverse talent the Academy needs to fulfill those diversity goals.

Whatever the impetus, documentarians get to vote on the final Oscar ballot, just like everyone one else. And they seem likely to bring with them a taste for small, reality-based, and often serious films like, say, Moonlight or Spotlight, the last two Best Picture winners. So Oscar handicappers would do well to factor in that growing pool of documentarians when they get down to predicting the next round of honorees.