Those benefits appear to be going to tenants in high-end and midrange buildings nearby. Presumably, their landlords see new competition and adjust their own rents accordingly. But Ms. Li finds that new housing has no effect on rents more than 500 feet away, and it doesn’t appear to affect rents for lower-end units nearby (those landlords probably don’t see new luxury towers as direct competition).

In a separate study, Brian Asquith and Evan Mast at the Upjohn Institute and Davin Reed at the Philadelphia Fed find a similar set of results across 11 major cities, including Atlanta, Austin, Chicago and Denver. They look at new buildings of at least 50 units constructed in lower-income, central-city neighborhoods. They estimate that these new buildings decrease rents by 5 percent to 7 percent for their immediate neighbors, relative to what we’d expect rents to be if the new buildings were never built.

Neither study means that rents actually fall. Rather, they suggest that new buildings slow the pace of rent increases in the kinds of neighborhoods that developers have already identified as hot. By the time those developers arrive — particularly with plans for large-scale projects — rents are most likely already rising rapidly.

“Wealthy people are already looking to move into the neighborhood,” Mr. Mast said of how he would explain his findings to a heated public meeting over such a proposal. “So we can build this building that will give them the sort of unit that they want to live in. Or if we don’t, they’ll take a unit nearby and renovate it.”

That logic may be little comfort to longtime residents, particularly those concerned about neighborhood changes that go beyond rent prices. But it addresses at least one argument against new housing.

“These results don’t deny the reality of gentrification,” said Ingrid Gould Ellen, a professor at N.Y.U. and an adviser to Ms. Li. “They don’t deny the reality of crushing rent burdens. They simply suggest that building more housing in a neighborhood isn’t going to exacerbate those high rent burdens and may even help to alleviate them.”

One caution comes from research by Anthony Damiano and Chris Frenier, doctoral candidates at the University of Minnesota who looked at new large-scale buildings built across Minneapolis. Like Mr. Mast and Ms. Li, they find that new supply helped ease rent pressure for higher-end units nearby. But at the bottom third of the market, they concluded that new buildings had the opposite effect, accelerating rents.