Researchers in Italy analyse 47,000 films to come up with list of those most referenced

When a tornado carried Dorothy off to a land of witches and talking scarecrows it was not only Oz that she and her companions ended up taking by storm: new research suggests the world of movies was never the same again either.

Researchers in Italy have declared the Wizard of Oz the most influential film ever made, outstripping others in how much it has inspired and been referenced in the film industry.

The research team came to their conclusion after analysing more than 47,000 films across 26 genres, using references noted in the online movie database IMDb. The authors note that the database is biased towards films from the west, with the majority produced in the US.

The team did not consider short films, adult films and those with no link or reference to other movies. They used a combination of four different mathematical approaches to explore the connections between movies, taking into account factors including the number of references a film received and whether the films that referred back to it were themselves influential.

The results, presented in the journal Applied Network Science, reveal the top 20 influential films were all made before 1980 – perhaps unsurprising given that older films have had longer to make a mark – with Star Wars and Psycho scooping second and third place respectively. Other high entries include Citizen Kane, Metropolis, Casablanca, Dr Strangelove and Battleship Potemkin.

“It is exactly the purpose of our research on most significant movies: to find the ones that are important from an historic point of view,” said Dr Livio Bioglio, a co-author of the study, from the University of Turin.

Among other insights, the team found that countries such as India, Japan and the US tended to produce movies without input from other nations, while Belgium and France appeared to collaborate often.

What’s more, they found different countries peaked in influence at different times: the most influential films produced in Italy clustered around the 1960s, while in Germany it was films from the 1930s that packed the greatest punch.

The team devised a separate approach for ranking actors and directors in order to get around the bias towards older movies. The team awarded points to individuals depending on how influential a movie they were involved with was compared with other films released in the same year. Only films released before 2010 were considered, as most films after that date have yet to make a mark on other movies.

The results place Alfred Hitchcock at the top of the list of directors, with Steven Spielberg in second place, and the top two male actors were Samuel L Jackson and Tom Cruise. Lois Maxwell, who played Miss Moneypenny in many of the Bond films, and Carrie Fisher were the most influential female actors.

The analysis also threw up extra findings. “For example, we noticed that Japanese monster movies – the so-called kaiju, such as Godzilla – released in the 50s have a great influence on western cinema,” said Bioglio.

The 20 most influential films ever made

1. The Wizard of Oz (1939)

2. Star Wars (1977)

3. Psycho (1960)

4. King Kong (1933)

5. 2001: A Space Odyssey (1968)

6. Metropolis (1927)

7. Citizen Kane (1941)

8. The Birth of a Nation (1915)

9. Frankenstein (1931)

10. Snow White and the Seven Dwarfs (1937)

11. Casablanca (1942)

12. Dracula (1931)

13. The Godfather (1972)

14. Jaws (1975)

15. Nosferatu (1922)

16. The Searchers (1956)

17. Cabiria (1914)

18. Dr Strangelove or: How I Learned to Stop Worrying and Love the Bomb (1964)

19. Gone with the Wind (1939)

20. Battleship Potemkin (1925)