From the press release:
"The survey, which was conducted by the Institute for Local Self-Reliance over an 8-day period in January, gathered data from 2,768 independent businesses. It found that those in places with an active "buy local" campaign run by an Independent Business Alliance or Local First group reported revenue growth of 5.6% on average in 2010, compared to 2.1% for those elsewhere.
Business owners active in these community initiatives also reported a wide range of benefits, including greater customer loyalty and more awareness of the needs of independent businesses among city officials.
Similar surveys over the last three years have produced similar results."