Organizational Interfaces exist when two or more organizations interact with each other in order to achieve objectives that would not be possible or feasible by operating independently. When organizations become interdependent an entire new class of vulnerabilities emerge, and understanding these is vital. Ideally, probabilistic risk assessments (PRAs) account for the reliability of hardware, software, humans and the interfaces among them. From a reliability and PRA disciplines perspective, very little is available in terms of methodologies for estimating the chances that OIs problems can contribute to risks. The objectives of this work are to address the following questions: 1) Are OIs important contributors to risks? 2) What are the ways/means of OI failures? 3) Can causal model of OI failures be developed? 4) Can improvements in the reliability discipline be made to incorporate the effects of OI failures?

The importance of OIs as contributors to risks were confirmed through an investigation on past accidents in different industrial and service sectors and identifying the evidence on how OI failures played a role. A set of OIs characteristics that provide an understanding of how deficiencies and enhancements in such characteristics can lead to or mitigate/prevent OI failures were proposed. These are derived from insights gained from the accidents reviewed, and from a review on organizational behavior theories and models.

The OI characterization was used to propose a Bayesian Belief Network causal model of OI failures for communication transfer. The model is built by means of a study conducted to gather empirical evidence on whether OI failures can be dependent on the OI characteristics. The evidence was gathered through a survey questionnaire to study causal factors of OI failures. The OI characterization was also used to develop OI Failure Mode and Effects Analysis (OI-FMEA) to be utilized as tool to incorporate the effects of OI failures in systems failure. The OI-FMEA was exercised to test if it provides enhancements on current Dynamic Position FMEA practices in the deepwater oil and gas well drilling industry. The exercise demonstrated that the OI-FMEA concepts were a powerful tool to identify serious risk scenario not realized previously.