Following a nine-month stretch of positive billings, the Architecture Billings Index (ABI) showed no increase in design activity in January.

As a leading economic indicator of construction activity, the ABI reflects the approximate nine- to 12-month lead time between architecture billings and construction spending.

The American Institute of Architects reported the January ABI score was 49.9, down from a mark of 52.7 in December. This score reflects a very modest decrease in design services (any score above 50 indicates an increase in billings). The new projects inquiry index was 58.7, down from the reading of 59.1 the previous month.

“This easing in demand for design services is a bit of a surprise given the overall strength of the market over the past nine months,” said AIA Chief Economist Kermit Baker. “Likely some of this can be attributed to severe weather conditions in January. We will have a better sense if there is a reason for more serious concern over the next couple of months.”

Key January ABI highlights:

• Regional averages: South (54.8), West (49.3), Midwest (50.8), Northeast (46.0).

• Sector index breakdown: multifamily (51.4), institutional (53.0), commercial / industrial (50.9), mixed practice (46.9).

•  Project inquiries index: 58.7.

• Design contracts index: 51.3.