The suite of OAA Contracts are organized numerically:

• OAA 600 – Long form contract to be used between an OAA Certificate of Practice holder and a client
  
• OAA 800 – Short form contract to be used between an OAA Certificate of Practice holderOAA Certificate of Practice holder and a client for use on less complex projects (derived from OAA 600)
  
• OAA 900 – Standard form of Subcontract between OAA Certificate of Practice holderOAA Certificate of Practice holder and SubConsultants (can be used with OAA 600, OAA 800, and other contracts)
  

Each contract comes in variants for Architects. There are corresponding usage Guides and Instructions for the contracts which provide background information about how to fill in and use the contracts.