客服中心最小人力需求之研究

Abstract

客服中心不但為顧客與企業間提供了對話與溝通管道，更可為顧客提供服務或進行促銷，可說是服務業的最佳代表。目前客服中心之話務人力需求估算主要是以歐蘭C公式將話務量預測值轉換而得，然而現今客服中心之服務範圍趨於多元化，而客服人員通常具有多重技能。再加上電腦與電話網路的結合，使得話務的自動指派更為智慧化，若以傳統之歐蘭C公式估算話務人力需求，則會因為其客服人員數為整數的限制而導致人力資源的閒置與浪費。在多重技能與話務指派自動化的考量下，可將每位客服人員之人力資源依其對不同技能之貢獻程度加以分割，如此將使人力資源的調度更為靈活，人力需求之估算也將更為合理。 本研究以一個由D公司提供話務量資料、客服人員具多重技能的個案客服中心台中分部為研究對象，該分部全時客服人員約150位，兼時人員約30位，主要可再分為銀行與信用卡部門，其上班時間為上午07:00至隔日深夜02:00，共有四種不同技能，並以一個月的資料進行話務人力需求估算。話務量資料主要是依據不同技能，將其分割為每15分鐘一個區間，每一種技能每日共計有76個區間。本研究首先放鬆傳統的歐蘭C公式中話務人力需求為整數的限制，發展出十分之ㄧ單位之人力需求轉換模式(modified Erlang C formulation)，使其在滿足預先設定的服務水準目標值的前提下，估算出更為合理的人力需求數，並將其與原有的歐蘭C公式加以比較。研究結果顯示，該模式將可較傳統之歐蘭C公式所估算者平均節省4.93%之話務人力需求。 此外，更將以前述的人力需求轉換模式與結果為基礎，進一步以整數規劃方法建立最小人力排班模式，以計算出在滿足各時段各技能排班人力大於或等於話務人力需求之限制下，各班別各技能之客服人員最小排班人力，並考慮加班或用餐及休息時間為彈性等不同情形對最小排班人力需求之影響。研究結果顯示，單純考慮加班僅能節省約3%的人力，而用餐及休息時間為彈性則可節省至少12%，換算為成本每年將可為該客服中心節省至少800萬元以上，即用餐與休息時間是否具彈性對於人力需求有較大的影響。而其結果也可使組織了解目前的人力供需情況等，進一步做出更適切的調度安排。

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.