Overnight ratings dipped slightly for the first full day of the 2012 NCAA Tournament. Four NCAA Tournament telecast windows on CBS, TNT, TBS and TruTV averaged a combined 5.6 overnight rating Thursday, down a tick from last year (5.7), but up 22% from coverage of the 2010 tournament on CBS alone (4.6). The 5.6 is the highest average overnight for the first Thursday of the NCAA Tournament since the current four-telecast format began in 1991. Overnight ratings for each of the individual telecast windows were not immediately available, reports Sports Media Watch.