||This article may be too technical for most readers to understand. (December 2012)|
A production assistant, also known as a PA, is a member of the film crew and is job title used in filmmaking and television for a person responsible for various aspects of a production. The job of a PA can vary greatly depending on the budget and specific requirements of a production as well as whether or not the production is unionized.
Television and feature film 
In unionized television and feature film, production assistants are usually divided into different categories: "Set PA", "Truck PA", "Locations PA", "Office PA", or "Set Runner" and "Extra PA or Daily" - Variations exist depending on a show's structure or region of the United States or Canada.
Office PAs usually spend most hours in the respective show's production office handling such tasks as phones, deliveries, script copies, lunch pick-ups, and related tasks in coordination with the production manager and production coordinator.
Set PAs work on the physical set of the production, whether on location or on a sound stage. They report to the assistant director (AD) department and key set PA if one is so designated. Duties include echoing (calling out) "rolls" and "cuts", locking up (making sure nothing interferes with a take), wrangling talent (actors) and background, facilitating communication between departments, distributing paperwork and radios, and related tasks as mandated by the ADs. Set PAs usually work 12- to 16-hour days with the possibility at the end of a shoot to work more than 20 hours a single day and are regularly the "first to arrive and the last to leave".
Commercial Set PAs share the same responsibilities as their Television and Feature Film counterparts (see "Set PAs" above),but also inherit additional responsibilities traditionally encompassed by other departments in the television and feature film structure. These responsibilities range from providing both critical and mundane production support equipment such as dollies, cranes, director's chairs and pop-up tents to standing in for talent and even filling in for other departments who might be shortstaffed. It is not atypical for a commercial set PA to be seen handling trash one minute, and the next minute assisting the electricians or grips with a set-up. A select group of commercial set PAs are given the responsibility of driving and managing the production and camera cube trucks. This responsibility is often given to the more senior PAs because it provides several extra days of pay.
Set PAs in commercials are more commonly hired by the production coordinator and/or production manager as opposed to an AD or key set PA. However, many commercial ADs will.
Standard rate for a commercial PA in the Los Angeles area is a flat rate of 200 dollars per day. On February 1, 2008, benefits for qualifying freelance PAs became available through the Producer's Health Benefits Plan.
Union vs. non-union 
No union currently exists for production assistants, but the affiliation of a production with a union (or unions) can affect the job responsibilities of a PA. Less unionized shows have more positions that can be serviced by non-union personnel; consequently, PAs on such productions may take on a greater variety of non-traditional duties. Examples of this would be a PA setting a light bounce (grip department) or driving a passenger van (teamster/transportation department).
In British Columbia, which has the third largest film and television production sector in North America, PAs are represented by the Director's Guild of Canada. Production Assistants represented by the DGC work in the Locations Department and work both on and off set with duties including locking-up the set, traffic control, echoing rolls, firewatching, and liaising with the public and location owners. The Key-PA is in charge of all the PAs and is the 1st ADs' right-hand man when it comes to do with the on set aspects regarding a location. From this position DGC PA's can move up through the Locations Department or the Assistant Direction Department as either a Training Locations Manager (TAL) or a Training Assistant Director (TAD), respectively. Office Production Assistants work in the production office as an Office PA and they work for the Production Manager, Production Coordinator, Assistant Production Coordinator, and / or other office staff in maintaining the work-flow in the office. From this position, Office PAs can work their way up through the office by becoming and Assistant Production Coordinator (APOC) which is unionized under IATSE 891. Pay for PAs according to the DGC Collective Agreement in BC is $205.00 (non-members) to $215.00(members) for a 15 hour day. An 8 hour day is approximately $118.00. For further information consult the Director's Guild of Canada.
In Quebec, The Set PA is part of what is called the "Unit Department" or "Régie". Usually, there is a Unit Manager, Asst. Unit Manager, Set PA, Truck PA, Set Runner, and the "dailies" as needed for street blocking and extra set ups. In other states and provinces these duties are often taken care of by AD Dept., Locations or Transport. The Unit manager and his/her team are the ones who deal with the daily logistics of shooting on location and/or in studio.
There are two film unions in Quebec: IATSE 514 and AQTIS: L’Alliance québécoise des techniciens de l’image et du son. In both cases the PA's are unionized.
Efficient relaying of information is a critical job function and a radio (walkie-talkie) is heavily utilized on set to communicate between the AD staff as well as all other departments. In addition a PA might also carry an assortment of pens and markers, spare radio batteries, a multi-task tool, aspirin, gloves, small light and a surveillance headset.
-  Director's Guild of Canada
-  BC Film Commission
- The Production Assistant's Pocket Handbook Popular how-to written by a PA for PAs. Used by professors at several film programs. Available as a PDF or handbook.
- The Anonymous Production Assistant A daily blog written by a working production assistant.
- Cash B's How To Become a PA A guide to all things related to a PA.