Digital Queue Management Systems: A Literature Review of Waiting-Time Estimation, Virtual Queues, and Service Operations

Digital queue systems represent service requests as trackable tokens, allowing progress to be monitored without the need for a physical line. The effectiveness of these systems is determined by how accurately they predict waiting times, how clearly they communicate updates, and how efficiently they support staff activities. This paper examines sixteen studies focusing on delay estimation, virtual queues, customer experience, and the evaluation of queue systems. The research highlights that recent service history and current queue status can provide reliable estimates, while fluctuating demand and limited data can affect accuracy. It also emphasizes that wait time information influences customer behavior, making it an integral part of the service experience rather than just an informational display. While studies show benefits in specific contexts, these findings cannot be directly applied to other service environments. We analyze the reviewed methods and their limitations, identify shortcomings in multi-organization queue systems, and connect these insights to the QueueEase system. The review recommends that evaluations should assess estimate accuracy, update reliability, access control, perceived fairness, and the workload of staff. QueueEase offers a prototype framework for this research; however, it has not yet been tested in a live pilot to confirm these outcomes.