JAMSHID MOHAMMADI ^[*] and EDUARDO DESANTIAGO ^{[ ]}
Department of Civil and Architectural Engineering, Illinois Institute of Technology
Chicago, Illinois 60616, USA

The assessment of the reliability of an engineering system to a great extent depends on performance data. Such data is obtained in a variety of ways. Most conventional methods utilize field or laboratory data. In cases where such data is not readily available or cannot be obtained through conventional means at a reasonable cost, data from experts can be utilized. In addition to the data from the experts, there may be cases where the correct approach to a reliability analysis may not be clear. In such situations, experts may have to be called to provide a direction as to what methods would be most suitable for conducting a rational reliability analysis. This chapter focuses on reliability analysis using this approach. Specifically, the significance of using experts in providing information on the reliability methods, data collection process and performance data from opinions expressed by experts are described. Different statistical methods in conducting tests on such data, identification of biases and methods to improve the outcome of reliability analysis using information from experts are also discussed.