Ranking the greatest films in horror history can be a tough assignment. Weighing The Exorcist against The Shining? Psycho against Halloween? These are the stuff of post-movie diner argument legend.
But that difficulty level is nothing in comparison with the punishing task of trying to rank horror franchises against one another. Take The Exorcist, for instance. The original is obviously one of the most frightening and unforgettable horror films ever made, but The Exorcist is also part of a five-film franchise; one that includes the likes of Exorcist II: The Heretic, Exorcist: The Beginning, and Dominion: Prequel to the Exorcist. Given those anchors around its neck, even having the original Exorcist in its fold doesn't necessarily guarantee the franchise as a whole a high spot on this list.
Each franchises' placement on this list is something of an "average quality" of all entries in the series.