JUMBO METHODOLOGY

Period 1880-1900 1900-1920 1920-1950 1950-2000

Jumbos > 250,000 ft2 > 500,000 > 1,000,000 > 2,000,000

Super Jumbos > 500,000 > 1,000,000 > 2,000,000 > 4,000,000

The chart of Jumbos and Super Jumbos seems simple in its mathematical doubling of building area in each category and period, but the numbers reflect extensive research and analysis of sources.

Statistics for the interior area of commercial buildings, both for the present day and historically, are difficult to find and are often highly confusing, since there is no consistent standard of measure. Some industry sources report figures for "gross building area" (GBA)--which is all the space within the walls, including service and common areas. Others use "rentable area," which would seem to be a smaller number, but can sometimes be larger, especially in New York. Early in the century, figures for rentable area referred to office space only and reportedly averaged around seventy to eighty percent of the GBA in an efficiently planned building. For the exhibition, we have gathered measures of each building1s area from various sources and have attempted to determine a reliable figure.

To create the categories of Jumbos and Super Jumbos, we have used New York buildings and statistics to establish the standards. Based on figures collected by the Real Estate Board of New York (REBNY) over the century, in particular, data compiled for their annual surveys of new construction (such as the hand-written lists seen in this case), we have estimated an average size for a commercial high-rise in four periods that represent the major cycles of construction since the 1880s. Jumbos and Super Jumbos thus contain twice or four times that area in the respective period.