A real choice exists today on a number of discoveries between platform-basedor subsea development solutions. Statistics from the Norwegian continentalshelf (NCS) show that fields developed with fixed platforms have asubstantially higher recovery factor. The potential for a later commitment toimproved oil recovery (IOR) is determined largely by the original developmentsolution. Through the use of cases and examples, this paper discussesprinciples for valuation of the enhanced flexibility offered by platform-baseddevelopment solutions and sequential subsea solutions. It illustrates thatvaluing the various types of flexibility is difficult, which leads to thefollowing question: Are development solutions being selected without takingsufficient account of option values?