Film producers fill a variety of roles depending upon the type of producer. Either employed by a production company or independent, producers plan and coordinate various aspects of film production, such as selecting script, coordinating writing, directing and editing, and arranging financing. During the "discovery stage", the producer has to find and acknowledge promising material. Then, unless the film is supposed to be based on an original script, the producer has to find an appropriate screenwriter.
For various reasons, producers cannot always personally supervise all of the production. For that reason, the main producer may appoint executive producers, line producers, or unit production managers who represent the main producer's interests. Among other things, the producer has the last word on whether sounds or music have to be changed or scenes have to be cut, and they are in charge of selling the film or arranging distribution rights. The producer's role can vary significantly from project to project and based on the circumstances and funding.
Whereas in television, the primary role of the producer has been to oversee all aspects of video production, in film and often in television today, this role is filled by the line producer. The line producer may manage a film's budget and maintain a schedule. The executive producer oversees the filmmaking with regard to film financing. They liaise with the line producer and report to production companies and distributors. Whether the person credited as "producer" or a person credited as "executive producer" has more input on a production is not always clear and is subject to change as the film is substantiated. Since filmmaking is a dynamic process, responsibilities can grow or shift in the process and credits for producers can get adjusted retroactively. For example, somebody hired as a "line producer" might later be credited as an "executive producer".
Because of these dynamics, all involved producers must agree on production standards from the start. Negligence in that matter can lead to a domino effect. Other producers are more involved with the day-to-day workings, participating in activities such as screenwriting, set design, casting, and even directing. Currently, because of the restrictions the Writers Guild of America screenwriting credit system places on writing credits, many scriptwriters are credited as "producers" instead, even though they may not engage in the responsibilities generally associated with that title. In this limited sense, the producer and the screenwriter may be the same person. Producers differ from Production Management (Production and Unit Managers and Production Coordinators) in part because the responsibilities of Production Management are more logistical than creative.