A summer advertising campaign launched by the Indianapolis Convention & Visitors Association helped produce more visitors and dollars for central Indiana, even though the organization spent less this year marketing the region.

The ICVA said Thursday morning that the half-million-dollar ad campaign resulted in 745,000 new visitors who spent more than $145 million in central Indiana.

Promotional spots airing in Chicago, Cincinnati, Louisville and St. Louis generated a $289 return for every dollar spent, according to data gathered by Carmel-based research firm Strategic Marketing & Research Inc.

The numbers represent a 15-percent increase in return on investment from 2008, although the ICVA said it spent 32 percent less promoting the metropolitan area—$504,497 this year compared with $740,152 in 2008.

“The awareness of Indianapolis and its many arts, cultural, entertainment and sports offerings continues to grow throughout the Midwest,” ICVA President and CEO Don Welsh said in a prepared statement. “These results are especially pleasing in the face of the difficult economy.”

The four-month campaign that began in May was most successful in Chicago and Louisville, which together accounted for about 83 percent of the new visitors, according to the research.

Strategic Marketing’s research, based on 900 interviews, showed the campaign produced slightly more than 745,000 visitors who spent an average of $195, down from $226 in average visitor spending in 2008.

Lodging accounted for $20.3 million of the spending. While Marion County received most of it—$15.9 million—surrounding counties benefited as well, including Hamilton ($3.6 million), Hancock ($434,688), and Hendricks ($281,782).

In addition, attractions and museums netted $11.5 million in visitor spending.

Area attractions that partnered with ICVA in the campaign were the Children’s Museum of Indianapolis, Conner Prairie, the Eiteljorg Museum of American Indians and Western Art, Indiana State Museum, Indianapolis Motor Speedway, Indianapolis Museum of Art and the Indianapolis Zoo.