| Summary |
Yu-Chih Lai，2006.06
Institute of Transportation Technology and Management
National Chiao Tung University
A call center not only provides communications between customers and enterprise, but also provides services and promotions. It can be regarded as the best representative of the service business. Nowadays the manpower demand of a call center can be mainly calculated by Erlang C formulation. However, the agents usually possess multi-skill and the automatic assignment of calls is becoming more and more intelligent. If we still use the traditional Erlang C formulation, it will lead to the waste of human resources because of the integer unit of manpower. Therefore, under the consideration of multi-skill and the automatic call assignment, we can divide the human resource into decimal unit to obtain a more reasonable manpower demand according to its contribution to different skills.
We conducted a case study of a call center’s division in Tai-Chung. The work hour is from 07:00 AM to 02:00 AM next day. It contains about 150 full-time agents and 30 part-time agents, and it can be separated into the banking and credit card departments with 4 different skills. First of all, we develop a decimal unit Erlang C formulation to acquire a more reasonable manpower demand which can satisfy the goal of telephone service factor set in advance. Comparing with the traditional Erlang C formulation, the manpower calculated by modified Erlang C formulation can save manpower for 4.93% in average.
In addition, we formulate the minimal workforce requirement model using integer programming based on the results of manpower demand mentioned above. Hence we can obtain the minimal workforce requirement to every period and skill under different situations including base case, overtime only, flexible rest time only, and overtime and flexible rest time. The result of our study shows that the influence of flexible rest time is more serious than that of over-time. It can save the workforce requirement for at least 12% when considering flexible rest time. Converting it for the manpower cost, we can save more than eight million dollars a year. |
