Janet Staiger argues that Hollywood films are never pure genres, because most Hollywood movies blend the love oriented plot of romance genre with other genres. Staiger claims that the genre of a film can be defined in four ways. The “id ealist method” judges films by a predetermined standard. The “empirical method” identifies the genre of film by comparing it to a list of films already deemed to fall within a certain genre. The “priori” method uses common generic elements which are identified in advance. The “social conventions” method of identifying the genre of a film is based on the accepted cultural consensus within society. Jim Collins claims that since the 1980s, Hollywood films have been influenced by the trend towards “ironic hybridization” in which directors combine elements from different genres, as in the case of the Western-Science fiction mix in Back to the Future 3.
A genre is always a vague term with no fixed boundaries. Many works also cross into multiple genres. In this respect film theorist Robert Stam has noted whether “genres really are out there in the world, or are they merely the constructions of analysts. “As well hehas asked whether genres are “timeless platonic essences or ephemeral, time-bound entities”. Are genres cultural bound or trans cultural? Stam has also asked whether genre analysis should aim at being descriptive or prescriptive. While some genres are based on story content (war films) others are borrowed from literature (comedy, melodrama) or from other media, (the musical). Some are performer based (the Fred Astaire and Ginger Rogers films) or budget based (blockbusters) while others are based on artisitic status (the art film), racial identity (Black Cinema), location (the western) or sexual orientation (queer cinema).
Many genres have built in audiences and corresponding publications that support them, such as magazines and websites. Films that are difficult to categorise into a genre are often less successful. As such, film genres are also useful in areas of marketing, criticism and consumption. Hollywood story consultant John Truby states that “you have to know how to transcend the forms (genres) so you can give the audience the sense of originality and surprise”. Some screenwriters use genre as a means of determining what kind of plot or content to put into a screenplay for a film. They may study films of specific genres to find examples. This is a way that some screenwriters are able to copy elements of successful movies and pass them off in a new screenplay. It is likely that such screenplays fall short in originality.
Screenwriters often attempt to defy the elements found in past works, as originality and surprise are seen as elements that make for a good film. For example European filmed spaghetti westerns changed the western film genre by deliberately avoiding many of the conventions of earlier westerns.
There are other methods of dividing films into groups beside genres. For example auteur (a filmmaker whose movies are characterised by a filmmakers creative influence) critics group films according to their directors. Some groupings may be casually described as genres although the definition is questionable. For example, while independent films are sometimes discussed as if they are a genre in and of themselves, independent productions can belong to any genre. Similiarly, art films are referred to as a genre, even though an art film can be in a number of genres.