Chopra & Meindl

1. Consider a supermarket deciding on the size of its replenishment order from Proctor & Gamble. What costs should it take into account when making this decision? The main cost categories for the supermarket’s inventory policy are material costs, ordering costs, and holding costs. Material cost is the money paid to Proctor and Gamble for the goods themselves. Ordering costs, also called procurement costs, are incurred by requesting the goods from the supplier and are fixed in the sense that they do not vary with the size of the order. Examples of such fixed costs are the labor required to place the order, handle the resultant paperwork and the transportation fee to ship the order. The holding cost is the cost to carry one unit in inventory for a specified period of time, usually one year. This cost is variable and includes the cost of capital and all of the costs associated with physically storing inventory – shrinkage, spoilage or obsolescence, insurance, the cost of capital, the cost of the warehouse space, etc. 2. Discuss how various costs for the supermarket change as it decreases the lot size ordered from Proctor & Gamble. As the lot size ordered from the supplier decreases, the holding cost (variable with respect to lot size) decreases. As the lot size decreases, the ordering cost remains the same, but the annual ordering cost will rise since the total number of orders each year must increase. As the lot size decreases, the cost of the materials will drop on a per-order basis but will stay the same on an annual basis since total annual demand hasn’t changed. The exception to this occurs if the supplier has a price break for an order size above a certain threshold; in this case the cost of the goods might increase if the reduced order size is not sufficient to trigger a substantial per unit discount. 3. As demand at the supermarket chain grows, how would you expect the cycle inventory measured in days of inventory to change? Explain. As the demand at the supermarket chain grows, we would expect the cycle inventory as measured in days of inventory to also increase, although the increase in cycle inventory is only 40% of the increase in demand. This is because the relationship between the optimal lot size Q* and the annual demand D is [pic]. Since D is under the radical, its doubling to 2D does not translate to a jump from a Q* to a 2Q* order; it translates to a jump from a Q* to a 1. 4Q* order. 4. The manager at the supermarket wants to decrease the lot size without increasing the costs he incurs. What actions can he take to achieve his objective? One action would be to simply decrease the lot size and let the robust nature of the EOQ model work its magic. The total cost curve on either side of the optimal order quantity, the Q*, is relatively flat, so movements in either direction have little impact on total annual procurement and carrying costs. If greater cuts in lot size are desired, the manager can aggregate multiple products in a single order. Recall that the EOQ model is based on a one-product-at-a-time assumption; if multiple products are aggregated, then the fixed procurement cost is spread over all of the items and dramatic lot size reductions are possible. If the same products are being ordered by another supermarket in the same chain (or at least by stores that are willing to cooperate) the combined orders can be delivered by a single truck making multiple stops, thereby reducing transportation expense. Other techniques that should be deployed when aggregating across product lines include advanced shipping notices and RFID tags that will make inventory tracking and warehouse management simpler. 5. When are quantity discounts justified in a supply chain? Quantity discounts are justified in a supply chain as long as they are the fruits of a coordinated supply chain and maximize total supply chain profits. For commodity products for which price is set by the market, manufacturers with large fixed costs per lot can use lot size-based quantity discounts to maximize total supply chain profits. 6. What is the difference between lot size-based and volume-based quantity discounts? Lot size discounts are based on the quantity purchased per lot, not the rate of purchase. Lot size-based discounts tend to raise cycle inventory in the supply chain by encouraging retailers to increase the size of each lot. Lot size-based discounts make sense only when the manufacturer incurs a very high fixed cost per order. For commodity products for which price is set by the market, manufacturers with large fixed costs per lot can use lot size-based quantity discounts to maximize total supply chain profits. Volume discounts are based on the rate of purchase or volume purchased per specified time period. Volume-based discounts are compatible with small lots that reduce the cycle inventory. If the manufacturer does not incur a very high fixed cost per order, it is better for the supply chain to have volume-based discounts. For products for which a firm has market power, volume-based discounts can be used to achieve coordination in the supply chain and maximize supply chain profits. 7. Why do manufacturers such as Kraft and Sara Lee offer trade promotions? What impact do trade promotions have on the supply chain? How should trade promotions be structured to maximize their impact while minimizing the additional cost they impose on the supply chain? Manufacturers use trade promotions to offer a discounted price and a time period over which the discount is effective. The goal of manufacturers such as Kraft and Sara Lee is to influence retailers to act in a way that helps the manufacturer achieve its objectives. These objectives may include increased sales, a shifting of inventory from manufacturer to retailer, and defense against the competition. Trade promotions may cause a retailer to pass through some or all of the promotion to customers to spur sales, which increases sales for the entire supply chain. What happens more frequently in practice is that retailers may choose to pass through very little of the promotion to customers, purchase in greater quantities, and hold this cheaper inventory in greater quantities. This action increases both cycle inventory and flow times within the supply chain. Trade promotions should be structured such that a retailer’s optimal response benefits the entire supply chain, i. e. , retailers limit their forward buying and pass along more of the discount to end customers. If the manufacturer has accumulated excessive inventory, then a trade promotion may provide sufficient incentive to the buyer to forward buy, thus drawing inventories down to an appropriate level. The manufacturer may be able to smooth demand by shifting it to a period of anticipated low demand with a trade promotion. Research has shown that trade promotions by the manufacturer are effective for products with high deal elasticity that ensures high pass-through (passing the discount on to the consumer) and high holding costs that ensure low forward buying, paper goods being the poster child for this combination. Trade promotions are also more effective with strong brands relative to weak brands and may make sense as a competitive response. 8. Why is it appropriate to include only the incremental cost when estimating the holding and order cost for a firm? The cycle inventory models discussed in the chapter are robust; thus incremental (variable) costs per lot size are more important than costs that are fixed with respect to lot size. The labor component of procurement or setup costs may be salaried; therefore changes in lot size do not impact this component.