## 6 Discussion  
Being able to select the most appropriate procurement order quantity can lead to relevant implications on service and cost performances. However, as syndicated with the simulation results, the most suitable procurement order quantity for the same demand depends on the supply reliability, i.e., the supply behavior. As a result, for the same demand and for the same product, there should be different procurement order quantities based on the procurement reliability of the supplier. By doing so, a manager can secure operations in the plant under their responsibility with complete planning that includes the supply deviations. Based on the need to consider the supplier's behavior, in the sense of their procurement reliability (in quantity and time) to generate robust procurement plans, the selection of differentiating procurement order quantities represents a key factor for logistics managers to design, optimize, and secure operations. To provide a framework for managers on how to select the most suitable POQ, Figure 9 presents a methodological sequence for this purpose while considering a given master production schedule and organizational strategy. With this information, five steps are to be followed to enable a continuous improvement process in the selection of the POQ that implies a global optimization of the supply chain. The first step consists of executing the planning--assuming a reliable supply. Then, in the second step, the expected supplier's behavior is to be considered to simulate what-if scenarios. With the results and the probability of different kinds of behaviors and reliability levels, in the third step, the selection of the suitable POQ can be performed. Afterward, in the fourth step, the execution in the planning time horizon, providing actual indicators, can be compared with the target indicators. Finally, after the comparison, the deviations with target goals influence the continuous improvement process based on the organizational strategy, which will imply, for instance, the need for more or less safety stocks in the next procurement planning cycle. Based on the current global situation, in which supply chain disruptions and shortages, production stoppages, and stock-outs are becoming increasingly common and are developing into a global supply crisis, the trend for procurement order quantities and related factors is expected to be as follows:  
* One expected strategy is to increase procurement order quantities as producers will try to secure operations considering the supply uncertainty, thus leading to increased ordering to cover the potential future lack of supplies;
* Another strategy is to maintain procurement order quantities with orders being placed in advance as producers expect supply delivery delays;
* A third strategy might be to order the same or more procurement order quantities distributed in lower order quantities assigned to different suppliers while considering the supply risk of each supplier and potential order cancellations. All three strategies lead--if orders are delivered according to planned dates--to an increase in the average stock levels. In an uncertain context, an increase in stocks up to a certain level will be beneficial when considering the opportunity costs of stock-outs that might arise. However, if there is no collaboration regarding transparency among supply chain partners, it could lead to the generation of a bullwhip effect that could then develop into a supply crisis. In this situation, suppliers and producers will give priorities depending on product margins or strategic factors as they might have a higher quantity in their order books than they are able to process. This prioritization leads to the supply of goods with differentiated strategies depending on the product margin, product characteristics, sector, geographical location, etc., which may imply there will be some products or sectors suffering more from the lack of supplies than others.