Typically, some degree of uncertainty exists in the value of geotechnical parameters at any site (e.G., Owing to insufficient data, natural spatial variability, or possible changes with time). Often this uncetainty must be quantified (e.G., In terms of probability distributions that express the relative likelihood of any value). Because of inevitable data base deficiencies, those probability distributions must be based to some degree on subjective assessments, reflecting personal opinions and judgment, consistent with all available information (site-specific and generic), and recognizing the entire range of possible values. Subjectively derived probability distributions can represent the opinions of individuals or of groups. There areproblems associated with either, which, if uncorrected, render the results suspect and difficult to defend. Various techniques have been developed to conduct subjective probability assessments with varying effort and success in mitigating such problems. Thus, the appropriate technique is that which provides the desired level of defensibility at least cost. This paper appears in transportation research record no. 1288, Geotechnical engineering 1990.
Abstract