What successful adaptation reveals about capability and dependence in healthcare: A Brittle Threshold perspective

Healthcare teams routinely adapt to changing demands by redistributing tasks, stretching roles, and reorganizing coordination. Although these adjustments can sustain performance, their immediate success provides limited insight into how they affect the conditions supporting subsequent adaptation. We examined how successful adaptation reorganizes collective work and what these changes might reveal about emerging limits to adaptability. Guided by Brittle Threshold as a sensitizing concept, we conducted a secondary qualitative analysis of 34 anonymized interviews from four studies involving hospital teams during COVID-19, military surgical resuscitation teams, rural emergency care teams, and a community-led mass vaccination initiative. The datasets provided accounts of adaptation under varied demands and constraints. Across settings, adaptation changed collective work through four connected domains: work redistribution, coordination reconfiguration, responsibility concentration, and human requirements. Similar adaptations were sustained under different conditions. Some were accompanied by shared learning, expanded skills, and alternative sources of support, while others maintained performance through continued dependence on particular individuals, restricted access, or sustained personal effort. These patterns could coexist within the same setting. Examining the relationships among the four domains revealed differences in how collective performance was organized and supported that were not apparent from successful task completion alone. The findings offer an empirically grounded approach to examining potential Brittle Threshold signals in everyday healthcare work. Rather than identifying particular adaptive behaviours as warning signs, they direct attention to changing configurations of responsibility, coordination, support, and human effort. This perspective can inform investigations of how healthcare teams sustain adaptability as demands change.