Integrating cultural and regulatory factors in the bowtie: Moving from hand-waving to rigor

Abstract

Recent analyses of major incidents, such as BP’s Texas City and Macondo disasters and the loss of the space shuttle Columbia, have moved from considering immediate factors and basic organizational failings to including cultural issues. Culture is, however, even more difficult to incorporate into incident investigations and analyses than are organizational factors. This chapter provides a structured approach to analyzing individual, organizational and cultural/regulatory factors based upon the bowtie methodology, using well-defined rules to distinguish three levels of causation. Level 1 (L1) analysis describes barriers implemented at the individual, team and immediate hardware level; Level 2 (L2) describes the organizational factors that support level one barriers; Level (L3) describes the cultural and regulatory environment that ensures that the organization implements L2thereby ensuring the integrity of L1 barriers. Incident investigation and analysis can be performed as a structured search for failed barriers at any or all of these three levels. Both organizational failure (L2) and problems with the safety culture and regulatory environment (L3) can be reliably and rigorously identified, rather than relying upon the intuitions of investigators. This approach allows safety managers to support a range of approaches. First it enables them to identify and rank safety critical controls as those that manage the largest number of threats to integrity; this allows for a risk-based approach to auditing. Secondly the approach allows a rigorous definition of common mode failure with reference to the number of shared barriers at a higher level of analysis. Thirdly the detailed bowtie supports the investigation process by providing hypotheses about which controls have failed, including organizational, cultural, and regulatory factors.