IT-operational risk management consists of identifying, assessing, monitoring and mitigating the adverse risks of loss resulting
from hardware and software system failures. We present a case study in IT-operational risk measurement in the context of a
network of Private Branch eXchanges (PBXs). The approach relies on preprocessing and data mining tasks for the extraction
of sequential patterns and their exploitation in the definition of a measure called expected risk.
Keywords sequential pattern - pre and post-processing - operational risk