Q. Why do projects always seem to cost more than expected?

In general this seems to stem from three causes. The first may merely be an overly optimistic cost estimate. Sometimes under-estimating is politically motivated to ensure project approval. Secondly some schedule delays inevitably translate into added costs for someone. Thirdly for the reason that most people have difficulty in fully understanding plans and specifications when the sponsor or else the users see the physical results of the project they then seek changes which cost significantly more to implement than they would have had they been made at the planning stage.