The Better Business Bureau will launch a new ratings system for businesses Tuesday.Charlie Mattingly with the bureau's Louisville office says the new, nationwide letter grade system will replace the less-detailed scale of "satisfactory" or "unsatisfactory."He says it's been test-marketed in other parts of the country."There have been about five Better Business Bureaus that have been testing the ratings scale for the past three years, and there's been a lot of work gone into trying to be sure it's as objective and comprehensive as possible," Mattingly said.Mattingly says the letter grade assigned to each business takes into account a company's complaint history, how it responds to complaints, how long it has been in business and other background information.The ratings will be posted on the bureau's website, www.bbb.org.