The American Institute of Architects' architecture billings index now is above 50—the benchmark for growth in design activity—marking what the organization says is the first monthly increase in the index since January 2008.

The 50.4 September score, which was up from 48.2 the previous month, reflects an increase in demand for design services, since any score above 50 indicates an increase in billings.

A separate AIA indicator called the new projects inquiry index also was up sharply, moving from 54.6 to 62.3, the highest mark since July 2007. That index is a barometer of construction activity and reflects the approximate nine- to 12- month lag time between architecture billings and construction spending.

"I think some pieces of the industry are starting to tuck their head off the ground and looking around for some signs of spring," says Kermit Baker, chief economist with the AIA. "I think we finally did get some good news."

To represent sustainable growth for the industry, the architecture billings index (ABI) needs to score consistently above 50 for a handful of months, Baker says, which he thinks likely will happen. Data for October isn't available yet.

Since the beginning of the year, the ABI has displayed erratic behavior, edging north early in the year, only to drop in the spring before starting a steady recovery in June, with scores always moving forward but never breaking the psychological barrier represented by the number 50.

Baker has been predicting for months that the ABI would break 50, but each time the index fell short of expectations. Now, though, with the positive trend started in June and September's 50.4 score, Baker is sounding more upbeat.

"I think it's a good positive report," he says.

While the institutional sector remains weak (the score in September was 47.9), the commercial and industrial sector is leading the recovery with a 56.3 score. Multifamily housing (the ABI doesn't track single homes), sat at 47 in September, and mixed practice at 44.2.

Baker says the trends represent a "traditional economic recovery unfolding." During the recovery phase, he says, commercial markets respond faster than institutional markets, which is the opposite of what happens at the beginning of a recession, where commercial falls first.

Since most architecture, engineering, planning, and environmental consulting firms are small, Baker believes the recently passed Small Business Jobs Act "will be helpful" in stimulating a recovery for the sector.

However, "what's going to help architecture firms is more construction activity," he says. "There are a lot of unemployed architects out there looking for work."