The Beatles' famous songwriting credit, Lennon-McCartney, doesn't distinguish between whether John Lennon or Paul McCartney wrote most, all, or some of a particular tune.

And to many fans, it doesn't matter. But three researchers recently utilized statistics and mathematics to determine whether John or Paul was the composer of 1965's In My Life.

The researchers analyzed dozens of songs by the duo, and discovered 149 distinct transitions between notes and chords that are present in almost all Beatles songs, and which were unique to either Lennon or McCartney's compositions.

In My Life was released on the Beatles album Rubber Soul. The lyrics, a personal meditation about one's life and loves, are inarguably Lennon's. But Lennon and McCartney disagreed about who came up with the melody.

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In a 1976 book, McCartney recalled that it was his work, saying, "I liked In My Life. Those were words that John wrote, and I wrote the tune to it. That was a great one."

But in a 1980 Playboy interview, Lennon said McCartney wrote only the harmony and the bluesy middle-eight melody.

So the researchers ran their statistical model twice, once to determine who wrote the middle-eight melody, and once to determine who wrote the rest of the tune.

Harvard senior lecturer Mark Glickman, one of the researchers, told Inverse that the "McCartney wrote the middle eight" theory seemed plausible.

"The middle eight sounds like something McCartney would write," Glickman said. "When the middle eight goes, 'So I know I'll never lose affection,' the note changes aren't on the beat, they're off the beat. So they're syncopated. And McCartney does that quite a bit."

But the data proved that theory wrong. The stats showed there's only a fractional probability that McCartney wrote any of the music.

"The probability that In My Life was written by McCartney is .018," Glickman said in a press release. "Which basically means it's pretty convincingly a Lennon song."

While the study adds an interesting fact to Beatle studies, for many fans, it was never an issue.

"Who in the world thought McCartney wrote this?" wrote one Twitter user. "It's got Lennon all over it."

Who in the world thought McCartney wrote this? It's got Lennon all over it. — The Conversational Intellectual (@TalkButNotFight) August 12, 2018

But It's not a worthless exercise. Glickman said in the release that the methods utilized can be used track additional chapters of musical history.

"This technology can be extended," he said. "We can look at pop history and chart the flow of stylistic influence."

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