• by Wayne Friedman , October 7, 2014

Though broadcast TV networks are pushing other rating metrics to show off big performances of their shows, live program-plus-same-day TV ratings are still important, as a closer proxy for C3 ratings -- the currency media buyers use to make advertising deals.

Nielsen C3 ratings are still the predominant “currency” in how TV networks get paid from advertisers -- even with growing C7 deals. C3 ratings are the average commercial ratings plus three days of time-shifted viewing.

This year, TV networks have been pushing for trade publications and others to tout live plus three- and seven-day program ratings. For some, this isn’t indicative of where TV program performance really is.

“Clearly, the intention is to demonstrate how much better ratings look after the additional playback has been added in,” says Brian Hughes, senior vice president of audience analysis for Magna Global USA. “The trouble is that live plus three program ratings are a poor predictor of the C3 numbers that we still use for most of our TV deals.”

Hughes says: “The live-plus same-day program numbers that become available the day after prime-time programs air are quite close to what the C3 ratings will eventually be.”

He says live-plus same-day ratings are never more than “two-tenths of a rating point away from the C3 numbers.” By way of comparison, “there can be more than a full rating point difference between C3 and live-plus-three total program numbers.”

For example, in the second quarter of this year, CBS averaged an identical 1.3 average rating among 18-49 viewers for both its live program-plus-same-day program rating and its C3 metric. Fox was also at identical 1.3 numbers.

But when looking at live-program-plus three-days numbers, both CBS and Fox improved to a 1.6, NBC and ABC each averaged a 1.4 adult 18-49 live-plus-same-day rating with its C3 rating a 1.5. Both networks jumped to a 1.8 rating when looking at live program-plus-three-day ratings.

C3 ratings are available much later than live-plus-same-day program ratings -- around a week and a half or more.

"Watching TV" photo from Shutterstock.