The best on-air campaigns for TV program promotions aren’t always with the TV broadcast networks -- and don't always have to have the most messages.A new study from TV advertising-marketing company Simulmedia says TBS, for example, has greater effectiveness for some of its recent TV program promo messages than the broadcast networks -- even with far less overall TV program promo messages. TBS garners a high 147 “spot power” index -- the index represents the conversion of those promo watchers to incremental program viewers. Only Fox was higher at 149, followed by CBS at 119, ABC with 87, and NBC at 59. The study looked at national on-air TV program promo campaigns collected by Kantar in February and March -- analyzing 1 million TV homes, calibrated with Nielsen data.TBS also scored well in “campaign effectiveness” -- which tallies how well a network bundles its promos into other dayparts and off-networks -- at a 114 index. Only ABC was higher at 116. Next was CBS, at 95; NBC, at 89; Fox was at 86.One of the major reasons for promo success, says Dave Morgan, chief executive officer of Simulmedia, in speaking to Media Daily News, is that TBS has access to its national inventory in other dayparts, 24 hours/seven days a week -- as well as getting their promos running off-network. Broadcast networks such as CBS, ABC, and NBC only have access 12 hours a day. Fox has even less, at five hours a day -- plus its weekend NFL football programming.TBS ran some 10.98 million ad exposures for TV promos on its network during the period. But the big three broadcast networks -- CBS, ABC, and NBC -- had significantly more: CBS, 55.4 million; NBC, 50.6 million; and ABC, 46.3 million. Fox was at 14.9 million.But the study says just a large number of ad exposures can be wasteful, and frequency of greater than five is inefficient. It also notes that ad exposures within seven days are optimal -- and after 14 days are wasteful. Through their associated/owned cable TV networks, NBC and ABC garnered high off-air viewership of their campaigns -- NBC, 6.6 million; and ABC, 3.0 million. TBS got some 1.43 million ad exposures off the network. Farther down the list, Fox was at 1.1 million, and CBS -- with far less off-network exposure from cable networks -- was at 84,147 ad exposures.The study says using TV promo time in late fringe is the strongest here, with weekday daytime the second-strongest; early fringe and prime are behind. “Prime is not the best,” says Morgan. “On a cost-effective basis, for example, weekday is better.”As Simulmedia has done with other TV-related advertising research, Morgan says Simulmedia will be releasing much of the data in its findings for the industry to analyze: “The more people start understand how TV is accountable and optimizable, that’s a good thing.”"Watching TV" photo from Shutterstock.