Empirical analysis of scaling and fractal characteristics of outpatients

•The inter-arrival time distributions of outpatients are fat tails.•The activity serves an important function in an FCFS system.•Outpatients behaviors are fractal with long-range correlation and non-linearity.

The paper uses power-law frequency distribution, power spectrum analysis, detrended fluctuation analysis, and surrogate data testing to evaluate outpatient registration data of two hospitals in China and to investigate the human dynamics of systems that use the “first come, first served” protocols. The research results reveal that outpatient behavior follow scaling laws. The results also suggest that the time series of inter-arrival time exhibit 1/f1/f noise and have positive long-range correlation. Our research may contribute to operational optimization and resource allocation in hospital based on FCFS admission protocols.