The Ultimate Harry Potter Fan Quiz: Find Out Which House You Truly Belong In

My all-time favorite project! And, at least at one point, the all-time most-read story on Time.com and the source of data for several peer-reviewed research articles. Let me tell you a bit about it because I think it’s a fantastic blueprint for future projects.

Ahead of the 25th anniversary of the first Harry Potter book, the Time editors asked me for something interactive to complement the wall-to-wall coverage. After rooting around for anything other than yet another Sorting Hat quiz, I acknowledged that it was inevitable. The challenge was how to come up with a set of questions and a formula to map them to the four houses that was defensible and honest.

By good chance, I know a behavioral scientist who studies personality named Jason Rentfrow who connected me to Fritz Gotz, a graduate student (now professor). Fritz is a brilliant experimentalist and a dyed-in-the-wool Harry Potter fan. He was perfect. Together, we crafted a 21-question survey that polled readers on 5 different well-validated personality traits (Machiavellianism, Humility, etc.) that the Sorting Hats mentions in its badly metered soliloquies at the start of the fall semester.

Here’s where I think there’s room to replicate this project: Since we didn’t have the cooperation of Rowling, we needed a valid way to map the 5 real personality traits to the four fictional schools. So I recruited a few dozen avowed Harry Potter superfans to take the 21-question quiz on behalf of four characters from each house, answered each question as Harry would, or Draco would, and so forth. Since we knew the houses each of these characters is in, this became the training set for a fairly straightforward machine learning exercise that my colleague Pratheek Rebala put together. And it works beautifully (but not too beautifully). We had reverse engineered a fictional talking hat.

When users take the quiz, their answers are piped through the same equations that can correctly assign the fictional characters to the correct house (based on remarkably consistent evaluations of their fictional personalities by non-fictional people). Still, I didn’t really know if it had worked until I made the first map of the real-world results.

Millions of people have taken the quiz since, with nearly 3 million of them donating their anonymized responses back to Fritz and his colleagues for use in their research. I love this partnership. No money ever changed hands and we both got something extraordinarily valuable: A wonderful feature backed by great science on Time’s end, and untold volumes of data (fully cleared by the academic ethics board) on the scientist’s side.

It’s a partnership that can exist between any content platform and research group, so long as there’s a hook to attract readers regardless of whether they consent to the research part. The Sorting Hat worked naturally because it is intrinsically a personality meter and many of us had already wondered how we’d be sorted. And we knew people will take endless personality quizzes. It’s not the only such gauntlet in fiction, though. Particularly in fantasy. Those kids are perpetually undergoing trials, poor lambs.