Ask a critic to name the most influential film of all time and Citizen Kane might top the list. Ask an algorithm, and the answer is The Wizard of Oz.

Researchers at the University of Turin have developed a computer programme that measures the success of a film not by box office takings or positive reviews, but by how many times it is referenced in other films and how many spin-offs it engendered.

They assessed more than 47,000 films and found that The Wizard of Oz, that staple of Christmas viewing starring Judy Garland and released in 1939, topped the list. It was followed by the original Star Wars film and Alfred Hitchcock’s Psycho.

The algorithm used the Internet Movie Database (IMDb) website as its source material.

“The success of a film is usually measured through its box office revenue or through the opinion of professional critics; such measures, however, may be influenced by external factors, such as advertisements or trends, and are not able to capture the impact of a film over time,” the researchers said, adding that their method challenges the idea that “the best movies are simply the ones that sell more, like any other product".