“…In the literature, Porteus (1985) first introduced the concept and developed a framework for investing in reducing EOQ model setup cost. The framework he proposed has encouraged many researchers to examine set-up/ordering cost reduction (e.g., Keller & Noori, 1988;Kim, Hayya, & Hong, 1992;Nasri, Affisco, & Paknejad, 1990;Paknejad, Nasri, & Affisco, 1995). We examine two continuous review integrated inventory models in which the buyer offers backorder price discount to the patient customers with outstanding orders during the shortage period to secure customer orders, and analyze the effects of increasing investment to reduce the ordering cost.…”