How Lay First Aid Teams Coordinate May Shape Performance in Simulated Emergencies

When a traffic accident unfolds, the people who reach the injured first are rarely paramedics. They are bystanders who improvise, form ad-hoc groups, and attempt first aid before professional responders arrive. A new controlled simulation study from Sweden examined how such immediate responder teams coordinate with one another over time, and whether the structure of that coordination can predict how well the group performs. The findings, published in Advances in Simulation, suggest that a nonlinear measure of coordination dynamics carries information that conventional aggregated team measures do not.

The research team, led by Wilhelm Brodin, Fredrik Fernlund, Carl-Oscar Jonson and Erik Prytz, recruited sixteen groups of three participants, a total of 48 people, from a large university and the surrounding city in southern Sweden using convenience sampling. The sample was 58% male, 40% female, and 2% preferred not to answer their gender. Just over half of the participants, 56%, had prior first aid training, and the cohort included six emergency response professionals who were deliberately distributed across different groups rather than concentrated in any single team.

Each group faced a simulated traffic accident scenario. Trained subject matter experts rated the first aid performance of every group, providing an external benchmark against which coordination patterns could be tested. To make the analyses comparable across teams, the researchers restricted their behavioral analysis to the first 10 minutes and 28 seconds of each scenario, ensuring that every group contributed an identical window of activity.

The central methodological question was how to quantify coordination. The researchers coded participants’ coordinative behaviors, defined as the behaviors team members use to coordinate teamwork, using the Co-ACT framework. They then compared two analytical approaches. The first was a conventional aggregated approach, summarizing how often specific coordination behaviors occurred. The second was multidimensional recurrence quantification analysis, a nonlinear method that captures the temporal structure and dynamics of behavior over time rather than collapsing it into simple totals.

Recurrence quantification analysis rests on the idea that complex systems leave traces in the way their states repeat over time. In this study, the key derived measure was the rate of recurrence of coordinative behaviors, essentially how often the same coordination patterns recurred across the team during the observation window. Emergency response is widely described as complex and chaotic, yet methods designed for analyzing complexity have rarely been applied in this context, which is precisely the gap the study set out to address.

Two groups were excluded because of incomplete data, leaving 14 groups in the final analyses. The results were striking in their asymmetry. Rate of recurrence of coordinative behaviors significantly predicted first aid performance, with a standardized coefficient of -0.57 and a p-value of .02. In contrast, none of the four aggregated post-experimental measures of coordination reached statistical significance. Action implicit coordination yielded p = .37 with β = -0.31, action explicit coordination p = .97 with β below 0.01, information implicit coordination p = .99 with β = 0.01, and information explicit coordination p = .68 with β = -0.14.

The significant association was negative. Higher recurrence rates of coordinative behaviors went together with lower expert-rated first aid performance in this scenario. The authors interpret this cautiously, suggesting that behaviors not captured by the Co-ACT analysis, such as task work including chest compressions or bleeding control, may have had more influence on the quality of the first aid provided, at least in the current scenario. In other words, teams that repeated the same coordination patterns may have devoted relatively more of their activity to coordinating and less to the hands-on interventions that experts rewarded.

The study is explicitly exploratory, and its conclusions are correspondingly measured. The authors describe the results as initial evidence for the predictive power of recurrence rate on first aid performance in ad-hoc first aid groups, not as a definitive law of team behavior. The sample was small, drawn by convenience from one Swedish region, and performance was assessed in a single simulated scenario type. The negative association is a statistical relationship observed in this experiment, not a demonstrated causal mechanism, and the authors themselves note that unmeasured task behaviors could account for the effect.

What the study does demonstrate, in the authors’ view, is the usefulness of controlled scenarios for studying complexity in the provision of first aid. By holding the scenario constant and analyzing identical time windows across groups, the design allowed a nonlinear complexity measure to be compared directly against traditional aggregated team metrics. The recurrence approach detected a signal that four conventional measures missed, offering a concrete example of what complexity science can add to emergency response research.

The implications extend to practitioners as well as researchers. Ad-hoc responder groups are a common and poorly understood feature of real accidents and disasters, and little has been known about how their coordination evolves over time or how it relates to the quality of aid delivered. If recurrence-based measures continue to show predictive value in larger and more varied studies, they could eventually inform how lay responders are trained or how emergent teams are supported during the critical first minutes of an emergency. For now, the study stands as an early, carefully bounded demonstration that the temporal texture of teamwork, and not just its quantity, may matter when bystanders become first responders.

Subject of Research: Coordination dynamics and first aid performance in ad-hoc immediate responder groups in a simulated traffic accident

Article Title: Comparing aggregated and nonlinear measures of coordinative behaviors in immediate responder first aid groups: a controlled experimental simulation study

Article References: Brodin, W., Fernlund, F., Jonson, C.-O., & Prytz, E. (2026). Comparing aggregated and nonlinear measures of coordinative behaviors in immediate responder first aid groups: a controlled experimental simulation study. Advances in Simulation, 11(1), Article 82. https://doi.org/10.1186/s41077-026-00501-3

Image Credits: AI Generated

DOI: 10.1186/s41077-026-00501-3

Keywords: first aid, emergency response, team coordination, recurrence quantification analysis, simulation study, ad-hoc groups, complexity science, Co-ACT framework, nonlinear dynamics, bystander response, team performance, Sweden