Theatre's that employ union members create and agreement. This agreement stipulates the conditions, work related rules, recognitions, and details of the relationship between the theatre and the union members. Actor's Equity and the agreements they have with the various producing organizations around the United States is the most common to the live theatre industry. You will find AGVA unions in force in areas where variety entertainment is more the norm. Show towns like Las Vegas and Atlantic City will have a higher percentage of AGVA related agreements. Likewise, major opera towns will have opera houses with agreements with the AGMA union . Though it is important to remember that each union has it's agreements and unions can contract with other unions. It can all get very muddled.
For our purposes, we will concentrate on the Equity agreements.
If you go to the Actors Equity Web site (www.actorsequity.org) you will see in their navigation bar at the top a designation titled "Document Library". In the document library you will find a lot of information about Actor's Equity; everything from about Equity to information on Worker's Compensation. You will also note there is an agreements choice. If you make that choice it will take you to the rule books for each agreement. At last count I counted 69 rule books. When I began as a union member back in the 70's there were less than half of those agreements.
Take a moment to scroll down through the choices. You will note that some are specific to particular productions or locations. Everything from Menopause the Musical to the Madagascar Live agreement. Note that some are more general than others. For example, you have the LA area theatres and the Chicago area theatres. Some are specific to locations such as the production contract and Off Broadway contract.
Scroll down some more and towards the bottom you should encounter the URTA agreement. URTA stands for the University Resident Theatre Association otherwise known as URTA. In short, URTA was founded as a way for Universities to contract union members. Most large land-grant Universities are governed by boards of directors. Unions sign contracts with producers and not Boards of Directors. Universities contract URTA who contracts the actors who work at the Universities. The Universities pay the organization the costs and overheads of the actors while the organization charges dues and a percentage to the University for this service. Make sense?