Ever since Harry Potter first donned the Sorting Hat in J.K. Rowling‘s wizarding world series, millions of fans have wondered which of the four Houses they would be assigned on their first evening at Hogwarts: Gryffindor, Ravenclaw, Hufflepuff or Slytherin.

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Over the years, many sites have aimed to answer that question with multiple-choice quizzes drawn from anecdotes in the seven books. In honor of the 20th anniversary of the first volume’s publication on June 26, we thought it was high time to answer this question more rigorously: by teaming up with social scientists from Cambridge University to create a scientific-based quiz on which House best matches your personality. Now it’s your turn to take the quiz, and find out which House is the closest statistical match to your personality. You’ll also see how well you matched the other three houses.

(For the complete quiz, click here.)

To accomplish this, we worked with the researchers to develop a 21-question quiz compiled from several well-established scientific personality surveys, choosing questions that related to prevalent themes in the books. Over several weeks, we recruited hundreds of Harry Potter fans to take this survey on behalf of 20 different characters from the books, five from each House. The tens of thousands of data points we gathered gave us a detailed portrait of how different personality traits correspond to the personalities of members of each of the four Houses.

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In the spirit of many other projects where TIME has partnered with social scientists to allow readers to participate in their research, this quiz invites you to anonymously submit your responses to the researchers, which will contribute data to their studies.

It may seem a little unusual to apply the sophisticated field of personality psychology to a fictional universe, but a close reading of the Harry Potter canon — or in many of our cases, several close rereads — suggests something interesting: The Sorting Hat is itself a personality test! So it made perfect sense to try and deconstruct that process into a scientific survey.

Fortunately, there’s a rich body of science devoted to this topic. Unlike the popular Myers-Briggs personality test, which has little proven scientific merit, social scientists have developed a range of personality surveys that are well-researched and show statistically rigorous differences in how people behave. The best-known of these is called the “Big Five” test, which measures five traits: “Openness to experience,” “Conscientiousness,” “Extraversion,” “Agreeableness” and “Neuroticism.” You may recall seeing a condensed version of this survey in TIME’s feature on which state your personality best matches.

The 21 questions in the Harry Potter personality quiz are drawn from both the Big Five test and a handful of other well-studied personality inventories that measure other traits that are commonly seen in the Harry Potter novels, like “courage” and “humility.” The survey was assembled by Cambridge psychologists Friedrich Götz and Joe Scott in collaboration with TIME. The data we collected on the personalities of Harry Potter characters, from Harry himself to Professor Snape and Luna Lovegood and many others, shows that there are significant differences in the personality traits of characters from different Houses.

When you take this quiz, we analyze your responses and compare them to how closely they match each of the four Houses, using a standard statistical model designed to measure the relationship between datasets. Your affinity for each House is measured independently, so it’s very possible that your personality closely matches two different Houses — a phenomenon that the Sorting Hat itself is well familiar with, given its history of waffling between two Houses when a character’s personality isn’t an obvious match for one. As many fans have noted, for example, Hermione Granger’s ferocious pursuit of knowledge resembles the studiousness associated with Ravenclaw more than Gryffindor — a puzzlement that Rowling acknowledges on Pottermore.com: “The Sorting Hat spent nearly four minutes trying to decide whether it should place Hermione in Ravenclaw or Gryffindor.”

Note: This quiz is not endorsed or associated with J.K. Rowling, Pottermore Limited or Warner Bros.

Write to Chris Wilson at chris.wilson@time.com.