The contract documents, and the order they win in

• The contract is not one document. It is a set, and the set is defined inside the agreement itself. The agreement, the conditions of the contract, the drawings, the specifications, addenda issued before execution, and modifications issued after it.
• Order of precedence decides which document wins when two of them disagree, and a well-drafted contract states that order rather than leaving it to argument.
• The usual hierarchy runs: modifications, then the agreement, then addenda in reverse order of issue, then supplementary conditions, then general conditions, then specifications, then drawings. Later beats earlier, and the negotiated beats the standard.
• Addenda are issued before bids are opened and become part of the contract. Change orders are issued after award. Confusing the two is a reliable exam trap because both modify the documents.
• Between the drawings and the specifications, the specifications usually govern on materials and quality; the drawings govern on quantity and location. Where the contract is silent, that convention is what a court tends to apply.
• Figured dimensions govern over scaled ones. Never scale a drawing to resolve a conflict when a written dimension exists, and a note on the drawing beats the drawing it sits on.
• Anything shown on one and not the other is still required where the documents say they are complementary - which they almost always do. "It wasn't on my drawing" is not a defence when the specification called for it.

NASCLA Guide ch. 5