TA (Tentative Agreement) - A formal, signed agreement that once ratified by both parties becomes part of the Collective Bargaining Agreement. TA's can be used to update sections of the contract such as salary schedules. There are no expiration dates on TA's.

MOU (Memorandum of Understanding) - A formal, signed agreement that serves as an addendum to the Collective Bargaining Agreement (CBA). An MOU usually addresses an issue that emerged during the term of the agreement, and it represents the mutual understanding between the parties on that issue. Most MOU's will be in effect for a specific period of time and unless renewed, will no longer be valid after expiration.