This is a really cool read. The objective was evaluating whether two ergonomic methods could reveal the Death Star’s critical thermal exhaust port flaw. Notably, it uses an interesting fictional example from the film to tell an important narrative for real-world application.
The methods were:
1) HE-HAZOP (Human Error Hazard and Operability) analysis; said to represent the ‘deterministic world-view’;
2) WDA (Work Domain Analysis); a systems-model which describes system constraints. In discussing some differences between the methods, it’s said that HE-HAZOP generates more normative descriptions of a system while the WDA is formative, where “the constraints shape all possible behaviours within the system rather than script those that are observed to take place and/or designed to take place (p413).
A Star Wars expert group built/reviewed the outputs. Researchers guided the group on how to perform the analyses ‘by the book’, aiming to see if the flaw emerged. A HTA (hierarchical task analysis) was developed to inform the HAZOP.
Participants weren’t experienced at HAZOP, but balancing this was that they knew the flaw. An important consideration for the use of these methods was that participants were to strictly apply the methods by the book.
As expected, HE-HAZOP excelled at producing fine details but:
a) took twice as long as the Rebel Alliance had in the film to analyse the Death Star data;
b) didn’t detect the actual flaw. (It did explore other narratives on improvements, though).
Whereas the analysed tasks (as part of the HTA) were said to be explicitly related to the thermal exhaust port, the HE-HAZOP didn’t identify it. Noted is that the HAZOP analysis came close to identifying the issue via referring to unwanted debris that could enter the exhaust port and the benefit of placing a grate over to stop it. Authors note that this exercise surprised the participants on its ability to help them think and learn about how this fictional system could fail (and expanding their understanding of it compared to before the exercise).
Feedback from participants indicated a focus of the HE-HAZOP on particular hazards, like the build-up of heat from the thermal exhaust port (compared to the failure mode in the movie – a proton torpedo fired down the port).
As discussed by the authors, while the HAZOP did identify a large number of potential system failings, none were particularly strongly connected to the actual failure mode in the film, where “The infamous Thermal Exhaust Port, down which proton torpedoes were fired leading to the battle station’s complete destruction, activated very few HE-HAZOP guidewords, certainly far fewer than other system components” (p419).
Thus, one recommendation from the HE-HAZOP to increase the size of the exhaust port (to counter the build-up of heat) and knowing in advance of what happened in the film, was “surprising and highly paradoxical” (p419).
The WDA:
a) excelled at speed + a wider overview at the cost of detail;
b) actually identified the critical flaw. It also met the Rebel Alliance’s time constraint.
In comparing the methods, participants felt that the WDA wasn’t as good as HE-HAZOP regarding the fine detail of analysis, but was “better at ‘providing a good overview’, ‘better for strategising’ and perhaps most importantly, ‘a lot quicker’” (p418).
As highlighted, in contrast with HE-HAZOP which didn’t result in the actual flaw being identified, the WDA did result in identifying the fault and many others – including uploading a destructive computer virus which was influenced by the narrative from Independence Day.
Authors suggest systems methods may be a good choice for aspiring Rebels in order to destroy/study complex things like Death Stars. A weakness of the Imperial Empire was its scale and complexity.
In seriousness, the findings are used to discuss considerations around the selection of analysis methods, for instance challenges with reductionist and normative methods, for trying to study complex sociotechnical systems.
Authors: Guy Walker, Paul Salmon, Melissa Bedinger and Neville Stanton, 2016, Theoretical Issues in Ergonomics Science.
Study link: https://doi.org/10.1080/1463922X.2015.1130879
Link to the LinkedIn article: https://www.linkedin.com/pulse/what-death-star-can-tell-us-ergonomics-methods-ben-hutchinson
SafetyInsights.org 