This digital document is a journal article from Ecological Economics, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.Description: Contingent valuation has been used for over 30 years to reveal preferences for non-market environmental goods. Recent research has questioned the assumption that consumers posses fixed and well-defined preference orderings for such goods and suggests that individuals may need to form values for unfamiliar goods during the CV exercise itself. In this paper, we investigate how and why WTP is influenced by time to think, differing information levels and the opportunity to deliberate in a group setting for an unfamiliar good (red kite reintroduction) and a familiar good (green energy from wind power). For the Red Kite Project, we find that after several rounds of valuation final mean WTP is significantly different from initial mean WTP and that information, time to think and the opportunity to deliberate all influenced the valuation process. For the familiar good (wind power), mean WTP is not significantly different. Our overall conclusion is that whilst ''one-shot'' CV surveys may be appropriate for environmental goods that are familiar to participants (e.g. recreation benefits), they are not appropriate for less familiar goods (rare species) where the CV exercise should act as a 'preference engine' by giving participants time to think, information sufficient to their needs, and the opportunity to deliberate.