Formula fiction refers to writing that relies on a standard set of plot devices, themes, and stock characters, and a style similar to other novels or short stories in the genre. The phrase is almost never used in a complimentary fashion, and generally denotes texts that are not literary, but rather commercial or middle-brow.
Plot devices and stock characters
Forumla fiction appears in a number of literary genres, and dominates some, such as fantasy, romance, thriller, and science fiction. Common elements in fantasy might be the wise woman or elder or oracle, the protagonist who passes through a literal or metaphoric trial by fire, the dream of utopia and the threat of its destruction. In romance there could be the embittered, jilted or otherwise hurt man or woman who succumbs to the power of love, the high-flying woman who loses everything but is 'rescued' by the man she finds love with, or the couple who hate each other at first sight, but fall in love by the end. In thrillers there is often a deadly virus or plot to assassinate a public figure and the action moves around the world, or there is a stalker or serial killer on the loose, and since the 1990s, toying with the very detective hunting him down. These repetitions are called Hollywood Cycles when used in films.
Genre versus formula
While formula fiction is often found in genre writing, they are not the same thing. A genre operates with a set of conventions that readers are familiar with and do not need explained – say, the aristoratic English detective or the divorced, lonely, alcoholic cop, the murder of a seemingly harmless person or the inexplicable theft of a trinket, and the overheard conversation, the eagle eye, and the mislaid mail – and work a compelling but not entirely predictable story around them. Well-regarded genre fiction has an emotional depth or finesse in literary technique that formula fiction lacks. Characters are round, plots unique, and language near literary, or at least not riddled with clichés.
Mass market literary writing can be formula-driven, too, such as confessional stories of binge eaters or drug users, Jewish childhoods, or a mid-life crisis ending in bright resolution. Popular culture and much middlebrow culture are rich sources of formula fiction.