In popular culture, formula fiction is literature in which the storylines and plots have been reused to the extent that the narratives are predictable. It is similar to genre fiction, which identifies a number of specific settings that are frequently reused. The label of formula fiction is used in literary criticism as a mild pejorative to imply lack of originality.
Formula fiction is similar to genre fiction. The label of genre fiction is typically assigned because of the reuse of settings, content, layout, and/or style. The label of formula fiction is assigned because of the reuse of plot, plot devices and stock characters.
Genres like high fantasy, Westerns and science fiction space opera often have specific settings, such as a pseudo-Medieval European setting, the Old West, or outer space. Approaching a given genre, certain assumed background information covers the nature and purpose of possible predictable elements of the story, such as the appearance of dragons and wizards in high fantasy, warp drives in science fiction, or shootouts at high noon in Westerns. These set-ups are taken for granted by the genre conventions, and need not be explained for the reader anew... though it should also be noted that these elements can easily be treated subversively as well, playing with some of the preconceptions inherent in formula fiction.
The formula is defined specifically by predictable narrative structure. Formulaic tales incorporate plots that have been reused so often as to be easily recognizable. Perhaps the most clearly formulaic plots characterize the romantic comedy genre; in a book or film labeled as such, viewers already know its most basic central plot, including to some extent the ending. This does not always prove to be detrimental to a given work's reception, however, as the popularity of the aforementioned genre demonstrates.
Formula fiction should not be confused with pastiche (the mimicking of another work or author's style), though the latter by its nature may include elements of the former; the same holds true of some parody and satirical works as well, which may well include formulaic elements such as common stereotypes or caricatures, or which may use formulaic elements in order to mock them or point out their supposedly cliché or unrealistic nature. Indeed, between parody, satire and such subgenres as romantic comedy, comedy as a whole often relies on either formulaic elements, or the mocking of such elements.
Formula fiction is often stereotypically associated with early pulp magazine markets, though some works published in that medium, such as "The Cold Equations", subvert the supposed expectations of the common narrative formula of that time.
The dissection and tracking of common formulaic tropes (as well as their subversions and new permutations) has become reasonably popular beyond strictly academic circles. (The Final Girl being one such example, as well as, to some extent, Campbell's The Hero with a Thousand Faces). Amateur circles have websites such as the TV Tropes Wiki.