The architecture billings index, an economic indicator of construction activity, turned positive in August, according to the American Institute of Architects. The index reflects the approximate nine- to 12-month lag time between architecture billings and construction spending. The August score was 51.4, following four months of declines and a very weak score of 45.1 in July. Any score above 50 indicates an increase in billings. The higher score reflects an increase in demand for design services, and the new projects inquiry index was 56.9, up sharply from 53.7 the previous month. "Based on the poor economic conditions over the last several months, this turnaround in demand for design services is a surprise," said AIA Chief Economist Kermit Baker. "Many firms are still struggling and continue to report that clients are having difficulty getting financing for viable projects, but it's possible we've reached the bottom of the down cycle." In terms of the types of architectural services sought, mixed practice (50.9) saw the most demand, followed by institutional (48.5), commercial/industrial (46.0) and multifamily residential (44.8). The data comes from a "work-on-the-boards" survey that is sent to a panel of AIA member-owned firms. Participants are asked whether their billings increased, decreased or stayed the same in the month that just ended as compared to the prior month. The results are seasonally adjusted to allow for comparison to prior months. Write to Kerry Curry. Follow her on Twitter @communicatorKLC.