Читать книгу Intermittent Demand Forecasting - John E. Boylan - Страница 75

The choice between the and measures depends on the immediate consequences of a stockout and the financial impacts of these consequences. If the customer is prepared to wait for the SKU to come into stock (as is common in wholesaling), then a backorder will be generated and there are two possible courses of action for the organisation:

1 Place an emergency order on the supplier for all the units of the item that have not been satisfied. The supplier is requested to satisfy this order in a shorter lead time than normal, to mitigate the poor service provided to the client(s).

2 Advise the client(s) to wait until the next replenishment order is due to arrive, after the usual lead time has elapsed. When the order arrives, the backorders will be released, subject to sufficient stock having arrived.

On the other hand, if the customer is not prepared to wait for the SKU to come back into stock (as is common in retailing), then there are two possible outcomes:

1 Sales of a substitute product.

2 A complete lost sale, with no substitute items sold.

In the backorder case, for the first course of action, there will usually be an additional price to be paid to the supplier for expediting the goods in a shorter time than normal. If this additional price is fixed, and not proportional to the number of units short, then the service measure may be appropriate. This is because it is based on the proportion of replenishment cycles for which expediting is necessary, rather than on the proportion of items not satisfied from stock.

For the second course of action in the backorder case, there is no expediting cost for the organisation, but there is a potential cost in terms of loss of goodwill. This also applies if the customer is not prepared to wait, although the loss may be mitigated if the customer is prepared to buy a substitute product. It was mentioned earlier that loss of goodwill is very difficult to quantify. However, a fixed cost does not seem appropriate. It is surely worse to be short by four units, with two client orders for two units not being satisfied, than to be short by one unit for one client. Instead, a cost that is proportional to the fraction of unsatisfied demand seems more suitable, as reflected by the measure.

If the customer is not prepared to wait and does not purchase a substitute product then, in addition to the indirect cost of loss of goodwill, there is also a direct cost of loss of profit to take into consideration. Again, a cost that is proportional to the fraction of unfilled demand seems appropriate, making the measure suitable.