The paper "Quantity Flexibility Contracts and Supply Chain Performance" by Professor Bill Lovejoy and his colleague, Andy Tsay from Santa Clara University, was published in Manufacturing & Service Operations Management in 1999. The paper delves into the concept of quantity flexibility in supply chain contracts and its potential to deal with demand uncertainties. This influential work formally captured the practice of “funneling” variability over time, whereby more variability is tolerated in earlier planning phases and less tolerated over time as the delivery date approaches. This paper has specifically led to further studies on the optimal design and effectiveness of supply chain contracts, enhancing the field’s understanding of tactical and strategic issues in supply chain management. Researchers have built on Tsay and Lovejoy's model to study the application of QF contracts in different industrial contexts and their interactions with various supply chain configurations. The concept and modeling presented in this paper have become a prominent part of the academic discourse on supply chain coordination, influencing subsequent studies in inventory management, order variability, and supply chain profitability. Thus, the paper's impact is significant and broad, inspiring much-needed research on flexible, cooperative strategies for supply chain optimization.