The Council on Tall Buildings and Urban Habitat (CTBUH) has changed the way it measures building height.

Announced on November 17, the Chicago-based organization now includes below-grade, open-air pedestrian entrances in its calculations; previously, measurements were made from the sidewalk outside the main entrance. CTBUH also eliminated a “height to roof” category due to increased use of spires, parapets, and other features.

Graph courtesy CTBUH

The modifications have prompted a slight change in the ranking of the world’s 10 tallest buildings. Skidmore, Owings & Merrill’s Burj Dubai, opening this month and rumored to rise 2,684 feet, will still reign supreme. But Chicago’s Trump International Hotel & Towers, also by SOM, gains 27 feet, moving it up from the no. 7 to the no. 6 spot; it displaces SOM’s Jin Mao Building in Shanghai.

“In 2007, with the knowledge that Burj Dubai would be significantly taller than any structure ever built, [we] met to review the criteria by which we recognize and rank the height of buildings,” explains Peter Weismantle, CTBUH height committee chairman. “The resulting revisions almost two years later reflect a general consensus of the committee in recognizing the most recent trends in tall building development around the world.”