The AIA

’s monthly Architecture Billings Index (ABI) dipped to a score of 48.4 in September, down from August's 49.7, the Institute announced today. The result, a score that is 7 percent smaller than a year ago in September 2015, touched a low point that it hasn't seen in more than four years, since June 2012. The ABI is a leading economic indicator of construction activity in the U.S., and reflects a nine- to 12-month lead time between architecture billings and construction spending nationally and regionally as well as by project type. A score above 50 represents an increase in billings from the previous month, while a score under 50, like this month, represents a contraction.

Indexes for both new project inquiries and design contracts went a notch lower in September to 59.4 and 51.4, respectively. But progress persisted, as both sectors reported scores above the 50 benchmark.

“This recent backslide should act as a warning signal,” said AIA Chief Economist Kermit Baker, Hon. AIA, in a statement. “But this drop-off in demand could be continued hesitancy in the marketplace to move forward on projects until the presidential election is decided. The fact that new work coming into architecture continues to slowly increase suggests that billings will resume their growth in the coming months.”

Two of four regions posted gains in billings in September. The South snagged the highest score at 53.4, despite a 0.6-point drop in score month-over-month that shows growth in the area decelerated a bit. The Midwest came in second with slight growth, at 50.1, which was then trailed by the West and Northeast at 49.5 and 44.0, respectively. (Unlike the national indexes mentioned above, the regional category are calculated as a three-month moving average.)

Poor performance was logged across sectors. The commercial/industrial sector is the only one that saw billings improve over the course of last month, slightly rising from 50.3 to 50.4. Institutional and mixed practices, which both read 50.2 as of August, slid into contraction in September, to 49.0 and 49.8, respectively. Things went from bad to worse in the multifamily residential sector, a stalwart of growth for the industry since the financial crisis of 2008, its score declining from 49.9 to 48.8, a 15-month low. (Results of the sector category are also calculated as a moving average of the past three months.)