This the most common method of construction services and is well established and recognized. In this arrangement, the architect or engineer acts as the project coordinator and they are hired first by the client.  The architect or engineer role is to design the works, prepare the specifications and produce construction drawings, administer the contract from inception to completion.

When their drawings are completely done or are in the final stages of being completed the client will then hire the contractor through either a negotiated contract, or a competitive bidding process.

A competitive bid process is administered by the architect and all submitting bidders bid the plans exactly as drawn with little to no feedback on cost savings or changes.   The client & architect then select the qualified contractor from the lowest bids.