The Architecture Billings Index (ABI) dipped slightly into negative territory in January, after a very strong showing in December. As a leading economic indicator of construction activity, the ABI reflects the approximate nine to twelve month lead time between architecture billings and construction spending. The American Institute of Architects (AIA) reported the January ABI score was 49.5, down from a score of 55.6 in the previous month. This score reflects a minor decrease in design services (any score above 50 indicates an increase in billings).