Worries over how long the credit crunch will continue to impact residential construction are having a spillover affect on lending in other construction markets. The Architectural Billings Index (ABI) reflected these jitters in September, falling 2.8 points for a score of 51.1. It was the index’s second down month in a row. The number of inquiries for new projects in September, meanwhile, rose slightly for a score of 61.4. The American Institute of Architects (AIA) compiles these indices based on surveys sent to 300 mainly commercial firms; any value over 50 indicates growth. Studies have shown a correlation between the ABI and construction spending nine to 12 months in the future.