Edited sentence: And the "Jack" format is no ratings winner in any market.CBS Radio programs a broad based Classic Hits format focusing on Adult Rock playing over 1500 songs known as "Jack" in many of their markets.Clear Channel, however, has stayed away from such a format.It would be similar to "Jack" except it would have a different name like "Ben FM " or "Mike FM".Some of these stations had live airpeople while others do not.They have not launched such a broad based format in any of their markets.They may well percieve "Jack" type formats as "Flavors of the Month" that do not have the staying power.This "Jack" format has no live local air personalities and is Rock Music intensive.This format is just too limited for long-term success.This kept CBS from adopting "Jack FM" in a few markets.When Such formats were launched in a few markets, competitors in other markets such as Greater Media, Cumulus, and other groups as a preemptive move would put this type of format on one of their stations.While it does decent in some places, it has very low ratings in other places