"Stacker compiled data on all horror movies to come up with a Stacker score, i.e., a weighted index split evenly between IMDb and Metacritic scores as of Oct. 8, 2021. To qualify, the film had to be listed as horror on IMDb, have a Metascore, and have at least 25,000 votes. Ties were broken by Metascore and further ties were broken by IMDb user rating. Because they don't fall under the "horror" banner on IMDb, classics such as "Jaws," "The Silence of the Lambs," and "The Sixth Sense" didn't make the list.
Every film that did make the list has been considered according to the cinematic history and development of horror. An exception was made on behalf of three essential horror movies, whose lack of a Metascore inaccurately reflects their place in film history: "Nosferatu," "Diabolique," and "The Cabinet of Dr. Caligari." Each of these films has a Stacker score that reflects its respective IMDb user rating and has been ranked accordingly."