Title: Design and Analysis of Diagnostic Service Centers


Abstract:  Nurse lines are call centers that provide advice to patients about what 
the most appropriate course of action is according to their symptoms. For example, 
visiting the Emergency Department (ED) versus visiting a physician. At nurse lines, 
as well as many other service centers, diagnostic accuracy is a key performance measure 
in addition to waiting time due to congestion. Furthermore, since longer service 
typically entails higher accuracy but also more congestion, managers must decide on 
the optimal service depth and the staffing level to effectively perform a diagnostic 
process between an agent and a customer. We study this type of "diagnostic service center" 
in a strategic queueing setting, in which customers have autonomy to decide whether to 
use the service center or not, based on their expectation of diagnostic accuracy and 
waiting time.

We model this problem as a multiple-server queueing system with the servers performing 
a sequential testing process. Analysis of our model shows that the optimal staffing 
level is such that all potential patients are enticed to use the nurse-line. Also, we 
show that when the optimal staffing level increases due to a change in the parameters 
of the environment, it is not necessarily accompanied with a decrease of the wait times. 
Finally, the intuition obtained from the analysis of our model allows improving rules 
of thumb in practical
staffing decisions. 

Key words : service operations, strategic queueing, diagnostic process, call center

 
Joint work with: 

Xiaofang Wang, Renmin University of China, Beijing, P.R.China 100872, xiaofang.wang@gmail.com; 
Laurens G. Debo, Graduate School of Business, University of Chicago, Chicago, IL 60637, 
ldebo@chicagogsb.edu; Stephen F. Smith, The Robotics Institute, Carnegie Mellon University, 
Pittsburgh, PA 15213, sfs@cs.cmu.edu