More Lines Are Usually Better When It Comes to Worker Speed

New operations management research from Syracuse University’s Martin J. Whitman School of Management finds that when customers wait in one long line and go to the next available server, those servers work more slowly than when servers each have their own queue. In “Humans are not machines: The behavioral impact of queueing design on service time,” Julie Niederhoff, assistant professor of supply chain management at Whitman, and her co-authors, Masha Shunko, University of Washington, and Yaroslav Rosokha, Purdue University, found that single-line queues may slow down due to the interdependence of the task. That is, clearing customers out is a shared task and each worker contributes toward that goal, reducing any one person’s responsibility.  Additionally, there is a less obvious connection between a worker’s effort and the changes in line length, a challenge known as feedback saliency. However, there are system design issues and other performance incentives that motivate workers in both settings.

“When workers have clear feedback on the number of customers in line and how quickly they are moving, it can affect motivation in different ways,” said Niederhoff. “It also helps if managers provide pay-per-customer or other financial incentives.”

The researchers used experimental simulations in the Whitman Behavioral Lab at Syracuse University to determine worker performance over a 10-minute work period. They manipulated customer arrival rate, payment structure, visibility of the queue and queue structure.

“One thing to note, though, is that we only measure worker speed in each setting. This doesn’t necessarily mean worse customer service. Slower workers might not always lead to lower customer satisfaction,” said Niederhoff. “For example, in settings where customers are not concerned about speed but, rather, prefer a slower and more-personalized service, a server slowdown may lead to an increase in customer satisfaction. This is something for a manager to consider.”

She added that in other situations, speed might be a vital part of customer satisfaction. Another important and well-known consideration in selecting queue structure is fairness as perceived by customers: social justice would favor single-queue systems due to the first-come-first-serve order of serving customers.  The new research on worker speed adds clarity to another element in the queue-design decision.

The research is forthcoming in Management Science.