5. In practice, it can be difficult to find the costs of holding stock. Why is this? How can these difficulties be overcome? Are there any other views of inventory costs that could be easier to work with? 6. What are the assumptions of the economic order quantity? How valid are these? What factors in real inventory control are not included in the economic order quantity model? 7. We have described some simple extensions to the economic order quantity, and could have looked at many more complicated models. When do you think that it is worth using a more sophisticated model, rather than using the guidelines given by a simple model? 8. Nobody likes waiting for a product they have decided to buy, so why would an organization deliberately work with shortages? 9. It is often difficult to find reliable costs for stocks. With shortages this seems almost impossible, how do you find a cost for loss of goodwill or reduced future sales? Does this mean that any analysis of shortages is inevitably based on flimsy evidence? 10. Every organization thinks that its problems with inventories are unique. To what extent do you think they are right? 11. What are the benefits of short lead times? How can these be achieved in practice