When stable performance misleads: A formal model of compensation-dependent systems

Abstract

Background. Reliable performance in sociotechnical systems depends on continuous human adaptation. Resilience engineering and Safety-II established adaptation as the mechanism through which systems remain safe, yet governance monitors its products — accidents, mortality, delays, and compliance — far more readily than the compensatory work producing them. Stable performance may therefore conceal progressive deterioration in underlying system condition.,Model. This paper develops a formal dynamic model linking structural gaps G(t), compensatory effort C(t), adaptive reserves R(t), and observable output O(t). The model distinguishes demand-driven deficits from design-generated burdens that recruit the same finite reserves but require different interventions. The resulting compensation-dependent system state is termed Persistent Compensatory Engagement. The model predicts that compensatory effort rises before reserves decline, reserve depletion precedes outcome deterioration, and the sustainability boundary contracts as reserves are consumed.,Evidence. Convergent evidence from healthcare and commercial aviation reconstructs this predicted sequence across independent research programs. Both sectors document widening structural gaps, escalating compensatory effort, and reserve depletion while outcomes remained stable, with deterioration only now beginning to emerge. A three-tier measurement architecture links each model variable to candidate indicators for prospective monitoring.,Implications. In compensation-dependent systems, stable performance is not evidence of safety, it is evidence that compensatory work is succeeding. PCE reorients governance from monitoring the products of adaptation to measuring the processes sustaining them, and from reacting to failure after it emerges to intervening during the interval when structural correction remains possible. It provides a formal, falsifiable basis for distinguishing structural resilience from compensation-dependent stability in high-consequence systems.