It’s an interesting contradiction:

Rihanna’s “Every Girl (In The World)” was a hit song that many successful Mainstream ACs acknowledged, even when doing so was a sonic stretch. Like Usher’s “DJ Got Us Falling In Love,” it was more aggressive than the rest of the music on most ACs, but it was also too popular with adult women for many PDs to ignore.

Rihanna’s “California King Bed” made it only to the mid 20s at a Mainstream CHR format that has been resistant to ballads for the last several years. She is a superstar artist. The song was a sonic fit with the format as we’ve understood it for years. In Eric Norberg’s AC Music Research Letter, it actually had a research story with AC listeners. And there was certainly enough lateral support that AC would not have had to start “California King Bed” from scratch. But without being a CHR hit, it was never worked to or played at Mainstream AC. (In fact, as best I can tell, it got zero Mainstream AC spins.)

In the story of those two records are many of the questions about the increasingly contemporary Mainstream AC format, its relationship with Mainstream CHR, and when and how AC finds its current music.

In the still-rap-heavy first half of the ’00s, there was little question of suitable music trickling down from CHR. A left-field song ratified and warmed up by Country (“Live Like You Were Dying”) or even Christian AC (“I Can Only Imagine”) had a great chance of taking hold at AC. And PDs were still relatively willing to play AC-only songs, even if they didn’t survive past the first library test.

Now, it’s easy for AC to take its cues from Mainstream Top 40. In doing so, though, AC is inheriting a lot of the format’s current biases. Ballads struggle to clear the top 10 (and sometimes even the top 15) at CHR. While it’s hard to imagine Adele’s undeniable “Someone Like You” running into the ballad buzzsaw at Top 40, neither that song nor Lady Gaga’s also-promising “You And I” are at the summit yet.

So should Mainstream CHR make decisions about the appropriate texture of Mainstream AC? Does the belief of many Top 40 PDs that “ballads + PPM = death” apply now to a different format with different usage and expectations? Will any ballads have to come from Country—the other format that can set AC agendas? Has CHR used PPM to detect a sea change in the tastes of adult women? Or are they perpetuating yet another PPM truism that will not be indefinitely true?

If, however, Mainstream CHR and PPM have accurately captured a shift in listener tastes that AC would be wise to acknowledge, what are the implications for the rest of the music on Mainstream AC, particularly those songs from the last 15 years? The move away from the ’70s has increased AC’s dependence on the ’90s and early ’00s songs in its library, most of which would not pass the long-held acid test for oldies: “could it be a hit today?” With that comes the apparent belief that the listener who wants only “DJ Got Us Falling In Love” and “California Gurls” from today’s menu also wants only “Walking In Memphis” and “100 Years” from the ’90s and ’00s.

There are still inconsistencies in the timing of CHR-to-AC crossovers. To its credit, Mainstream AC is moving rapidly on “Someone Like You,” and no longer running a year behind on Katy Perry, as it did at the outset with “Hot ’N’ Cold.” And yet, the determination on when a song is ready to come over from Top 40 or Hot AC is still inconsistent, perhaps because it reflects inconsistent info on when those songs reach critical mass with adult women. The AC charts reflect the music decision of those stations who find CHR crossovers every 6-12 months through library testing, stations that use online callout, and stations that have no research of their own and watch the AC charts.

So when and how should AC find its currents? Your comments are encouraged.