The unspoken theory: How `socio-technical systems' are used without being theorized in safety research

Socio-technical thinking is widely used in safety science, yet the concept of 'socio-technical systems' is applied in diverse and often inconsistent ways. Rather than reflecting a shared theoretical foundation, the term frequently serves as a broad label for different system perspectives, with substantial variation in how its core ideas are understood and operationalized. This literature review examines how the term is currently interpreted in recent safety research and discusses the implications of this diversity for theory and practice in complex work settings. The review shows that while some studies explicitly build on the classical socio-technical systems tradition of the Tavistock Institute, emphasizing principles such as joint optimization, autonomy, and participation, others use the term more loosely, drawing mainly on neighboring fields such as human factors, resilience engineering, or risk management. These patterns reveal differing assumptions about what constitutes a socio-technical system, ranging from structured, model-based views to more adaptive, practice-oriented understandings. The paper argues for greater theoretical clarity in the use of socio-technical concepts in safety science. Without such reflection, there is a risk of conceptual dilution and missed opportunities to build on the distinctive contributions of the classical socio-technical systems tradition in addressing contemporary safety challenges.

Keywords: Socio-technical systems, Safety science, Human factors.