ABI Reverses in September

Written by Sandy Williams

The Architecture Billings Index reversed course for the first time in seven months, slipping to a score of 49.1 in September from 53.7 in August. A score below the neutral 50.0 mark indicates a decrease in design services.

The new projects inquiry index slid to 59.0 from a reading of 62.5 the previous month, while the index for new design contracts lost 1.3 points to register 52.9.

“We’ve seen unexpectedly strong numbers in design activity for most of 2017, so the pause in September should be viewed in that context” said AIA Chief Economist Kermit Baker. “Project inquiries and new design contracts remain healthy, and the continued strength in most sectors and regions indicates stability industry-wide.”

September ABI highlights:

  • Regional averages: Northeast (56.9), South (54.0), Midwest (50.4), West (48.8).

  • Sector index breakdown: commercial / industrial (54.0), mixed practice (52.2), multi-family residential (51.0), institutional (51.0).

About the AIA Architecture Billings Index

The Architecture Billings Index (ABI), produced by the American Institute of Architects, is considered a leading economic indicator of construction activity, and reflects the approximate nine to 12 month lead time between architecture billings and construction spending. The regional and sector categories are calculated as a three-month moving average, whereas the national index, design contracts and inquiries are monthly numbers. The monthly ABI index scores are centered on the neutral mark of 50, with scores above 50 indicating growth in billings and scores below 50 indicating a decline.

Below is a graph showing the history of the AIA Billings Index and Inquiries Index. You will need to view the graph on our website to use its interactive features; you can do so by clicking here. If you need assistance logging into or navigating the website, please contact our office at 800-432-3475 or

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