Abstract. The business value of information technology (IT) services is often
difficult to assess, especially from the point of view of a non-IT manager. This
condition could severely impact organizational IT strategic decisions. Various
approaches have been proposed to quantify the business value, but some are
trapped in technical complexity while others misguide managers into directly
and subjectively judging some technical entities outside their domain of
expertise. This paper describes a method on how to properly capture both
perspectives based on a probabilistic business-driven model. The proposed
model presents a procedure to calculate the business value of IT services. The
model also covers IT security services and their business value as an important
aspect of IT services that is not covered in previously published researches. The
impact of changes in the quality of IT services on business value will also be
discussed. A simulation and a case illustration are provided to show the possible
application of the proposed model for a simple business process in an enterprise