A reusable simulation model to evaluate the effects of walk-in for diagnostic examinations

Enabling patients to walk in for their diagnostic examination without an appointment has considerable potential in terms of quality of care, patient service, and system efficiency. We present a model to evaluate the effect of implementing a combined walk-in and appointment system, offering appointments to all patients preferring or strictly requiring these, while enabling all other patients to walk in. In a combined system, appointments can be scheduled in periods with low walk-in demand to counterbalance the possible high variability in walk-in arrival rates. We develop a discrete event simulation model, combined with an intelligent algorithmic methodology for appointment schedule optimization, for evaluating the implementation of a combined walk-in and appointment system for diagnostic examinations. Our simulation model is reusable: its component-based structure and generic underlying logic enable it to automatically represent any type of diagnostic facility, for which it can then evaluate the effect of implementing a combined walk-in and appointment system. Applying this approach, we quantitatively investigate the impact of implementing a combined walk-in and appointment system for CT-scans, performing a case study at the Academic Medical Center (AMC) Amsterdam. Inspired by the results, the AMC CT-facility has implemented a combined walk-in and appointment system, thereby shortening patients' diagnostic trajectories, and decreasing the number of required hospital visits for many patients.