Critical fragility in sociotechnical systems

Here is the abstract and part of the introduction (giving examples of system breakdowns) of a fascinating and approachable analysis by Moran et al.  Motivated readers can obtain a PDF of the article from me. 

Abstract

Sociotechnical systems, where technological and human elements interact in a goal-oriented manner, provide important functional support to our societies. Here, we draw attention to the underappreciated concept of timeliness—i.e., system elements being available at the right place at the right time—that has been ubiquitously and integrally adopted as a quality standard in the modus operandi of sociotechnical systems. We point out that a variety of incentives, often reinforced by competitive pressures, prompt system operators to myopically optimize for efficiencies, running the risk of inadvertently taking timeliness to the limit of its operational performance, correspondingly making the system critically fragile to perturbations by pushing the entire system toward the proverbial “edge of a cliff.” Invoking a stylized model for operational delays, we identify the limiting operational performance of timeliness, as a true critical point, where the smallest of perturbations can lead to a systemic collapse. Specifically for firm-to-firm production networks, we suggest that the proximity to critical fragility is an important ingredient for understanding the fundamental “excess volatility puzzle” in economics. Further, in generality for optimizing sociotechnical systems, we propose that critical fragility is a crucial aspect in managing the trade-off between efficiency and robustness.

 

From the introduction:

 

Sociotechnical systems (STSs) are complex systems where human elements (individuals, groups, and larger organizations), technology, and infrastructure combine, and interact, in a goal-oriented manner. Their functionalities require designed or planned interactions among the system elements—humans and technology—that are often spread across geographical space. The pathways for these interactions are designed and planned with the aim of providing operational stability of STSs, and they are embedded within technological infrastructures (1). Playing crucial roles in health services, transport, communications, energy provision, food supply, and, more generally, in the coordinated production of goods and services, they make our societies function. STSs exist at many different levels, from niche systems like neighborhood garbage disposal, to intermediate systems such as regional/national waste management, reaching up to systems of systems, e.g., global climate coordination in a world economy.

 

In spite of the design of the STSs with the intention of providing stable operations, STSs display the hallmarks of fragility, where the emergence of nontrivial dynamical instabilities is commonplace (2). Minor and/or geographically local events can cascade and spread to lead to system-wide disruptions, including a collapse of the whole system. Examples include i) the grounding of an entire airline [e.g., Southwest Airlines in April 2023 (3)]; ii) the cancellation of all train rides to reboot scheduling (4); iii) a worldwide supply chain blockage due to natural disasters (5), or because of a singular shipping accident [e.g., in the Suez Canal in March 2021 (6)]; iv) a financial crash happening without a compelling fundamental reason and on days without significant news [e.g., the “Black Monday” October 19, 1987, stock market crash (7)]; or v) the global financial (and economic) crisis of 2008 that emanated from the US subprime loan market, which represented a small fraction of the US economy, and an even smaller fraction of the global economy (8).