If you think you know Taylor Swift’s music, chances are you don’t know it like Andrew Ledbetter does.

The chair of communication studies at Texas Christian University said his love story with Swift’s music began during graduate school.

“I was driving around Lawrence, Kansas—where I went to graduate school—and ‘Love Story’ came on the radio, and I remember thinking to myself, ‘I think I could be a Taylor Swift fan,’” Ledbetter recalled.

“My fandom just grew and grew from there,” he added.

Now, in what he calls his “research era,” Ledbetter wanted to test an academic theory.

“I was interested in interconnections among the song lyrics,” he said. “The songs that are most central have a lot of overlap with other songs, might tend to be songs that are the most popular.”

To test that, Ledbetter ran the lyrics from all 10 of Swift’s albums, out at the time, through a computer program to look for patterns.

“At what threshold do we say, ‘Okay, these two songs are connected?’” he asked.

That threshold turned out to be 13.

“If a Taylor Swift song—two Taylor Swift songs—share at least 13 words in common, then those two songs, mathematically, it makes sense to treat those as connected,” he said.

Thirteen is Swift’s self-proclaimed lucky number.

“Okay, she really is the mastermind. I’m sure there’s no way she could’ve planned out that level of detail, and there was a mathematic rationale for that cut-off, but I just really like that cut-off as a Swiftie,” Ledbetter said.

The results supported his theory.

“There are exceptions, but generally, the songs that are most central do tend to be songs that either are big hits or they’re perhaps fan favorites,” he said.

Ledbetter measured popularity using Spotify streams, critical reviews and social media mentions.

“‘All Too Well’ is a very central song. ‘Blank Space’ is a very central song,” he said.

His research is published in Communication Quarterly, a peer-reviewed academic journal.

And to keep from leaving any blank spaces, Ledbetter has since added Swift’s latest two albums to the dataset and shared those findings on his blog.

He believes the research offers insight into more than just pop music.

“I think it helps us understand Taylor Swift, but I think it also helps us understand, overall, how do we engage with stories in art, and what stories do we find most interesting and compelling?” he said.

As for what’s next?

“I would love to teach a seminar on Taylor Swift,” he said.

It’s all part of the life of a researcher and a fearless Swiftie.