Bilal M. Ayyub
This chapter addresses the critical role of data in risk analysis. It surveys data sources including in-house databases, industry statistics, reliability and maintainability databases, and literature-based data. Challenges related to data quality, relevance, and transferability are discussed. The chapter presents expert opinion elicitation as a structured method for addressing data gaps, detailing theoretical foundations, process design, expert selection, and elicitation techniques. Methods for model modification based on available data are introduced. By combining empirical data and expert judgment, this chapter supports robust and transparent risk modeling under data limitations.