stated preference to determine willingness to pay for a good, preferring to rely on people's revealed preferences in binding market transactions. Early contingent valuation surveys were often open-ended questions of the form "how much compensation would you demand for the destruction of X area" or "how much would you pay to preserve X". Such surveys potentially suffer from a number of shortcomings; strategic behaviour, protest answers, response bias and respondents ignoring income constraints. Early surveys used in environmental valuation seemed to indicate people were expressing a general preference for environmental spending in their answers, described as the embedding effect by detractors of the method. In response to criticisms of contingent valuation surveys, a panel of high profile economists (chaired by Nobel Prize laureates Kenneth Arrow and Robert Solow) was convened under the auspices of the United States National Oceanic and Atmospheric Administration (NOAA). The panel heard evidence from 22 expert economists and published its results in 1993. The recommendations of the NOAA panel were that contingent valuation surveys should be carefully designed and controlled due to the inherent difficulties in eliciting accurate economic values through survey methods. The most important recommendations of the NOAA panel were that: Personal interviews be used to conduct the survey, as opposed to telephone or mall-stop methods. Surveys be designed in a yes or no referendum format put to the respondent as a vote on a specific tax to protect a specified resource. Respondents be given detailed information on the resource in question and on the protection measure they were voting on. This information should include threats to the resource (best and worst-case scenarios), scientific evaluation of its ecological importance and possible outcomes of protection measures. Income effects be carefully explained to ensure respondents understood that they were to express their willingness to pay to protect the particular resource in question, not the environment generally. Subsidiary questions be asked to ensure respondents understood the question posed. "[CVM] produces estimates reliable enough to be the starting point of a judicial process of damage assessment, including passive-use values" and has been successfully used in such high profile cases as the Exxon Valdez oil spill. The guiding principle behind these recommendations was that the survey operator has a high burden of proof to satisfy before the results can be seen as meaningful. Surveys meeting these criteria are very expensive to operate and to ameliorate the expense of conducting