One of the things that old (or middle-aged) grumps say about pop music in current times is that it's predictable -- there's really no room for innovation or originality because so many of the songs are tailored to be hits rather than to express any creativity or art.
On the one hand, that's exactly right. Of course, it was exactly right when we middle-aged grumps were listening to pop tunes as well. The reason "Imagine" or "We Built This City" aren't dumber than "My Humps" or "Die Young" is the same reason there's an absolute zero temperature -- you can't reduce the energy level of a substance below zero and you can't get any dumber than John Lennon, Starship, the Black-Eyed Peas or Ke$ha did with those particular songs. Yes, it's packed pretty tightly down at the bottom, but to borrow a phrase from Messrs. Lieber and Stoller, even though it's always crowded, you still can find some room. Lady Gaga has built a career on that principle.
On the other hand, the idea that pop songs are predictable is only partially true, say about 60 percent. Scientists at the University of Bristol gathered some statistics of hit songs on the United Kingdom music charts. They examined several characteristics, such as loudness, harmonic complexity, tempo, time duration and so on. They measured which songs charted higher and which ones stayed on the charts longer. When they had done all of this, they developed an algorithm that tried to predict whether or not a particular song would be popular. Pandora does something similar when you create a "station" or playlist from a particular song.
Since they used hits from the last 50 years, they also charted trends in hit singles. Before the 1980s, danceability was not a factor in a song's chances to chart well, despite what kids rating records on American Bandstand would say. Slow-tempo songs and ballads were likely to do better during that same time frame than they would today.
Although the algorithm's overall success rate was about 60 percent, it did much better at predicting chart position during the first half of the 1990s and since the year 2000. It did a much poorer job of predicting chart success during the last few years of the 1970s and the early 1980s. The article suggests that may mean that these years were "particularly creative and innovative periods of pop music."
As someone in his teens and early 20s -- the prime pop-music-buying age -- during that period, I can't disagree. And I can also now say that pop music really was better when I was younger. It's been proven by science.