When several lines are better than one

New research by Wharton’s Hummy Song suggests that knowledge-based industries should rethink how customer service manages queueing, and how operational design can change organizational culture and improve performance.

We’ve all been in lines that seem to last forever, especially if we choose our queue at the checkout and the one next to ours is moving faster. You know the existential dread that comes along with standing in a dedicated queue and waiting interminably. To make service of all kinds more efficient, the predominant thinking in operations management is to form a single serpentine queue that feeds different servers—a pooled queue.

Three long lines of standing people at an airport.

Traditional operations management theory has determined that pooling is more efficient. And it may be, if tasks or widgets are the items in the queue and it’s machines, not human beings, that are processing them. In a system with dedicated queues, it’s possible to have one that’s empty and another queue that’s full but no way to rebalance this. If the queue contains customers, naturally they can switch to the empty queue. But when we consider job assignments, for example, these can’t just move across queues. So the dedicated queue is viewed as less efficient than a pooled one in terms of throughput and waiting time.

paper by Hummy Song, assistant professor of operations, information and decisions at Wharton, and her co-authors focused on waiting rooms in emergency departments and found that when a part of the emergency department (ED) at a Kaiser Permanente hospital in California changed from a pooled queue to dedicated queues, patients had shorter wait times and a shorter length of stay.

It’s unusual in operations management to consider people in all their humanity, with their own idiosyncratic biases and behaviors. In “Pooling Queues with Strategic Servers: The Effects of Customer Ownership,” forthcoming in Operations Research, the authors show that efficiency is improved across the system if organizations consider a concept that may be unfamiliar to scholars in this area: customer ownership.

Read more at Knowledge@Wharton.