As a contractor, you know that jobs always have some surprises that may cost you money. You build that risk into your bids. But when a job is substantially changed from the one you bid, you can end up paying a lot more than your built-in risk factor. Sometimes you can recover that money by proving that the owner held back superior knowledge. Superior knowledge is information about a jobsite that was known by the owner but not told to the contractor--and that was essential to bidding and performing the job.