The rating process is largely subjective and is ever evolving. A Policy Review Committee comprising MPAA and NATO officials monitors the Review Board and provides guidelines to follow when rating movies. At this time, the Rating Board rates movies as follows:
G -- "General Audience - All Ages Admitted": Applied when a film contains no nudity, sexual content, drug use or strong language. Violence is minimal and the theme of the movie is deemed appropriate for young children. According to the MPAA, a G rating does not indicate the film is a children's movie.
PG -- "Parental Guidance Suggested. Some Material May Not Be Suitable For Children": The Rating Board applies this rating when the members believe the film contains themes or content that parents may find inappropriate for younger children. The film can contain some profanity, violence or brief nudity, but only in relatively mild intensity. A PG film should not include drug use.
PG-13 -- "Parents Strongly Cautioned. Some Material May Be Inappropriate For Children Under 13." The MPAA added this rating in 1984 to denote films in which violence, profanity or sexual content is intense enough that many parents would not want to expose their younger children to the film, but not so intense as to warrant an R rating. Any movie featuring drug use will get at least a PG-13 rating. A PG-13 movie can include a single use of what the board deems a "harsher, sexually derived word," as long as it is only used as an expletive, not in a sexual context.
R --"Restricted. Under 17 Requires Accompanying Parent or Adult Guardian": The Rating Board applies this rating to movies the members believe contain a high level of adult content, such as harsh profanity, intense violence, explicit sexual content and extensive drug use. In some states, the minimum age to see an R rated movie unaccompanied is 18.
NC-17: "No One 17 And Under Admitted": Originally called X, this rating is applied to films the board believes most parents will consider inappropriate for children. It indicates only that adult content is more intense than in an R movie; it does not imply any sort of obscenity. As with films rated R, the minimum age to see a NC-17 movie is 18 in some states.
This rating process is entirely optional; no filmmaker is required to submit her film for a CARA rating. Most filmmakers do because most movie theaters in the United States use the ratings system, and it's harder to get them to show a movie if it's not rated. Filmmakers who do not submit their movies to the Rating Board are free to release their movie unrated or to apply any other rating system. They cannot use any of the above ratings, however, as they are trademarked. CARA is not associated with the U.S. government, and its film ratings have no legal meaning.
This rating system is used when movies come out in theaters and when they are released on video. It is intended only for use in the United States. Rating organizations in other countries apply their own ratings to U.S. movies, and the Rating Board rates submitted foreign movies with its system, disregarding the film's rating in any other country.