Research goal
PSAS takes a systems approach to safety and security. We create and evaluate tools and processes, based on systems thinking, for catching the expensive flaws, vulnerabilities, and mistakes that traditional methods often overlook. Finding them during design costs far less than fixing them after testing, certification, or an accident. Safety and security in modern systems need collaborative research across disciplines, based on sound systems engineering principles.
The work draws on several MIT schools (engineering, management, social sciences, and sciences) and on collaborators at other universities and in industry. PSAS affiliates include defense partners and organizations working on aircraft and air transportation, spacecraft, medical devices and healthcare, automobiles, railroads, nuclear power, energy, oil and gas, and other domains.
STAMP, STPA, and CAST
STAMP (System-Theoretic Accident Model and Processes) is an accident causality model based on systems theory and systems thinking. It treats safety as a control problem, so it covers causes that failure-based models handle poorly, such as complex software, human decision making and human factors, new technology, social and organizational design, and safety culture. Under STAMP, a loss can happen even when every component meets its specification.
Two popular analysis methods are built on STAMP:
- STPA (System-Theoretic Process Analysis) is a hazard analysis method for safety engineering. Its security form, STPA-Sec, applies the same analysis to cybersecurity.
- CAST (Causal Analysis based on System Theory) applies the model after an accident or incident, to learn as much as possible from it.
Both methods are now used around the world in almost every industry, including aviation, automotive, defense, healthcare, and energy. Newer STAMP-based methods, such as those for identifying leading indicators of increasing risk, are starting to be used in industry as well.
Tutorials, handbooks, and other STAMP materials
Consortium
We formed a cross-industry consortium to carry out collaborative research in system safety and security engineering. The consortium works on real problems that industries face today and on solutions practitioners can put to use now. The consortium description (PDF) has the details.
Applications and research areas
Research topics
Hazard analysis
STPA and other methods that find unsafe interactions, flawed requirements, and other causes beyond component failures.
Accident and incident investigation
CAST and other ways to learn as much as possible from accidents and incidents, and causality analysis more broadly.
Human factors
How automation and system design can induce human error, and how to design for the people who operate and supervise systems.
Security
STPA-Sec and other systems approaches to cybersecurity.
Safety in systems engineering
Building safety into requirements, architecture, and design from the start of development.
Leading indicators
Identifying leading indicators of increasing risk, so organizations can act before an accident happens.
Safety management
Management and operation of safety-critical systems, corporate governance and management decisions about safety, and evaluating safety management in an organization.
Certification, regulation, and standards
How STAMP-based analysis can support certification, regulatory oversight, and industry standards.
Culture and social systems
The role of culture and of social and legal systems in safety.
Industries
Examples of PSAS projects in each industry.
Aviation
- Safety certification in NextGen air traffic management
- Certification of integrated modular avionics
Spacecraft
- Evaluation of STPA on the JAXA H-II Transfer Vehicle (HTV)
- Designing for safety in a NASA/JAXA scientific satellite
- STPA in early architecture trade studies for a planned JAXA crew vehicle
Healthcare and medical devices
- A systems-theoretic approach to designing safer medical diagnostic devices
- Quality control in medical device manufacturing
- The role of culture and of social and legal systems in medical device safety in China
- Safety certification of software-intensive radiation therapy systems
- Learning from safety-related events: the role of mental models
Automotive
- STPA analysis of electronic throttle control systems
- STPA applied to adaptive cruise control
- Integrating STAMP-based analysis into the engine system design process
Rail
- CAST and STPA applied to railroad safety in China
Defense
- Investigation of a Coast Guard helicopter night rescue training accident
- Preventing fratricide in the Patriot missile system
- A systems approach to cybersecurity
Nuclear power
- Certification of digital shutdown systems in nuclear power plants
Oil, gas, and energy
- Leading indicators for process safety
- Investigation of a power plant gas turbine accident in China
Other applications
- A STAMP-based approach to automation decisions at a manufacturing quality inspection station
- A STAMP-based view of the 2008 financial crisis
Publications
Many PSAS papers, theses, and reports are free to download.