An STPA Primer

STPA is a new hazard analysis technique based on systems thinking and a new model of accident causation based on systems theory rather than reliability theory. Although STPA has been published and evaluated in many academic papers, it was not possible in those papers to provide a tutorial on STPA. STPA was also described in a book, Engineering a Safer World (abbreviated ESW in this primer), by Nancy Leveson. Since then, there have been many requests for a tutorial description of this analysis technique that includes lessons learned from practical applications, updates since the book went to print, and answers to common questions asked in classes and workshops. This STPA primer is our attempt to do so. It contains a detailed tutorial on how to use STPA, answers to frequently asked questions, and lots of real-life examples of its use.
This primer is not stand-alone, however. Users need to read Engineering a Safer World first to understand the foundations of STPA, the principles for analyzing organizational, human, and technical components of sociotechnical systems, the effective integration of STPA into system engineering processes, and other practical lessons. Throughout this primer, an attempt is made not to duplicate what is in Leveson’s book but to explain it further. References back to the book are made when something has already been thoroughly discussed there.