供应链绩效管理之库存测评

供应链绩效管理之库存测评

All methods of measuring inventory begin with a physical count of units, volume, or weight 单位、数量和数量的实物盘点. Measures of inventories are reported in 3 ways:

(1)Average aggregate inventory value平均库存总值

(2)Weeks of supply

(3)Inventory turnover

1.Average aggregate inventory value

The average aggregate inventory value is the total value of all items held in inventory for a firm.

We express all dollar values in this inventory measure at cost按成本价格, 按原价because we can then sum the values of individual items in raw materials, work-in-process, and finished goods: Final sales dollars have meaning only for final products or services and cannot be used for all inventory items. It is an average because it usually represents the inventory investment over some period of time.

☯Suppose that A is a raw material that is transformed into a finished product, item B. one unit of item A may be worth only a few dollars, whereas

[☎♒✆♦☪☜❒✌]然而one unit of item B may be valued in the hundreds of

dollars because of the labor, technology, and other value-added operations

performed in manufacturing the product. This measure for an inventory

consisting of only item A and B is:

Summed over all items in an inventory, this total value tells managers how much of a firm’s assets are tied up in inventory. Manufacturing firms typically

have about 25% of their total assets in inventory, whereas wholesalers and retailers average about 75 percent .

To some extent, managers can decide whether the aggregate inventory value is too low or too high by historical or industry comparison or by managerial judgment. However, a better performance measure would take demand into account.

2. 供应星期数Weeks of supply

Weeks of supply is an inventory measure obtained by dividing the average aggregate inventory value by sales per week at cost 按成本价的销售额. In some low-inventory operations, days or even hours are a better unit of time for measuring inventory. The formula (express in weeks) is:

Although the numerator includes the value of all items (raw materials, WIP, and finished goods), the denominator represents only the finished goods sold —at cost 按成本价格, 按原价 rather than the sale price after markups 加价 or discounts . This cost is referred to as the cost of goods sold . 【numerator [ ⏹◆❍☜❒♏♓♦☜])分子__ denominator [♎♓⏹❍♓⏹♏♓♦☜]分母__ markup [ ❍✈☐]加价】

3. 存货周转率Inventory turnover

Inventory turnover or turns is an inventory measure obtained by dividing annual sales at cost by the average aggregate inventory value maintained during the year.

value

inventory aggregate Average cost at sales Annual

turnover Inventory = ☯ Notes: The best inventory level, even when expressed as turnover , cannot be determined easily .