For the second week in a row, CBS's The Big Bang Theory has outscored Fox's American Idol in the 8 00-8 30 p.m. half-hour among total adults and adults 18-49. According to Nielsen Media Research, the sitcom on Thursday attracted 16.4 million viewers versus 15.8 million for the talent contest. That number for Idol was 24 percent lower than it was a year ago for the comparable episode. Nevertheless, the rating for Idol 's entire hour-long telecast was higher than any other show's. Another problem for Fox its new Howie Mandel-hosted Mobbed lost 40 percent of Idol 's audience at 9 00 p.m. and dropped the network to No. 2 in that hour.