Architectural billings increased slightly after two relatively soft months, but the increase represents a decline in demand for design services according to a report released by the American Institute of Architects (AIA) Wednesday. The new projects inquiry index, a measure of people asking for architecture work, dropped substantially from 57.7 to 53.1. The firm reported that its monthly Architecture Billings Index (ABI) rose almost two full points to 47.9 in July from 46.0 in June. The index was 45.8 in May and 48.5 in April. The AIA sets a benchmark value of 50 for its indexes: anything above that number is considered to be positive and anything below negative. The ABI’s monthly data is derived from questionnaires distributed 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. According to the proportion of respondents choosing each option, a score is generated, which represents an index value for each month. AIA reported the new project inquiries index declined substantially in July to 53.1 from 57.7. Kermit Baker, AIA's chief economist, told HousingWire in June that the decrease in demand for design services is counteraction against over improving or over investing in a home. In 2005, credit was cheap and house prices were appreciating rapidly. Over the five years, however, Baker said the houses became smaller. “There’s a greater concern over affordability,” he said in an interview. “Now, we’re seeing less of [special design floorplans] and more of the general purpose space, more open space in design, more flexible space.” The regional buildings index was highest in the South at 47.9, followed by the Northeast at 47.2, the Midwest at 46.7, and the West at 45.2. The index was the highest in the commercial/industrial sector (50.4), followed by the institutional sector (47.9), the multi-family residential secotr (47.5) and the mixed practice sector (42.9). Write to Christine Ricciardi.