3-1 Introduction
Inventory is a difficult asset to control—it arrives and departs company premises daily, is scattered throughout the warehouse and production areas (and possibly off- site storage locations), may contain obsolete or scrap items, can involve thousands of part numbers, can include items owned by suppliers or customers, and may be valued using a variety of techniques for both direct and overhead costs. We use con- trol systems to make it less likely that the units and costs associated with inventory are incorrect. This chapter begins with a discussion of control systems and then de- scribes a list of 68 possible inventory controls in such areas as in-transit inventory, inventory storage, obsolete inventory, and inventory transactions. Although it is not necessary to implement all of the controls noted here, it is a representative list from which one can pick those controls that are most likely to positively affect one’s in- ventory accuracy.
3-2 What Is an Inventory Control System?
When dealing with inventory, one should be concerned about three issues: (1) the physical quantity of goods in stock and (2) the cost at which they are valued, as well as (3) the proper billing of shipped goods. An inventory control system should be based on these issues. First, its design should minimize the risk that inventory will be lost through any number of means (e.g., pilferage, scrap losses, natural dis- asters). This does notmean that a vast array of controls should be installed that make it impossible to lose inventory, but at the price of burdening the materials manage- ment process with a multitude of non-value-added activities. On the contrary, one must customize the control system so that sufficient controls are in place to miti- gate the greatest risks of inventory loss, while avoiding those controls that have comparatively little impact on inventory losses.
Second, the control system should ensure that costs are fairly and consistently applied to inventories. These controls can cover a wide array of areas, such as au- tomation of transaction data entry to avoid entry errors, locking down access to the
unit of measure field in the item master file, and controlling the contents of the over- head cost accumulation pools. Many of these controls do not require additional labor to maintain once they are set up, so there can be considerably more controls over inventory costs than may be the case over quantities.
Third, it should ensure that goods shipped are appropriately billed to customers.
An inventory control system is less concerned with billing the correct amount to customers; instead, the main point is to ensure that the billing transaction is ap- propriately triggered by a shipment action.
All of these issues are affected by the accuracy of inventory-related transactions, which are dealt with in the final section of this chapter. The following sections de- scribe many possible controls over various aspects of inventory quantities and con- trols. They are intended to be a pool of possibilities from which one can make selections, rather than a mandatory array of control requirements.
3-3 Inventory in Transit
Inventory in transit is an area that is customarily ignored by control system design- ers, because they tend to think only in terms of on-site inventory. However, this can be a major problem area if the terms of inbound or outbound shipment specify that the company retains ownership of the goods either before or after its arrival at or departure from the company premises. Thus, the key control issues include identifi- cation of the ownership of any in-transit inventories, mitigation of ownership risk, and inclusion of owned in-transit items in inventory valuations. The following con- trols address these issues:
Ownership: Record intercompany inventory transfers in a central inventory database.If a company shifts inventory from one subsidiary to another, it is possible that the inventory will not be properly relieved from the shipping en- tity or added by the receiving entity, either of which can cause unit record error.
In addition, the receiving entity may record the inventory at a different cost than the shipping entity. Both problems can be resolved by recording inventory trans- fers in a central inventory database that is used by both subsidiaries. However, these central databases are expensive to purchase and maintain, and also require reliable online access by multiple locations.
Ownership: Audit both sides of all intercompany transfer transactions. As just noted, both sides of an intercompany inventory transfer can incorrectly record the transaction, resulting in incorrect consolidated financial results. One way to detect these issues after the fact is to regularly schedule an internal audit review of both the shipping and receiving transactions associated with a sample of in- tercompany transfers. These reviews should result in recommendations to alter the recording system to eliminate errors.
Ownership: Require a customer signature on every bill-and-hold document.
If a company builds products but does not ship them, it can still claim rev- enue under the assumption that customers have authorized the company to store the units on their behalf. This approach can lead to significant abuse of
revenue recognition, so a good control is to require all customers to sign a bill- and-hold transaction approval document. This document states that customers have authorized the off-site storage and accept ownership of the goods.
Ownership: Audit shipment terms. Certain types of shipment terms will require that a company shipping goods must retain inventory on its books for some pe- riod after the goods have physically left the company, or that a receiving com- pany record inventory on its books before its arrival at the receiving dock.
Although in practice most companies will record inventory only when it is phys- ically present, this is technically incorrect under certain shipment terms. Con- sequently, a company should perform a periodic audit of shipment terms used to see if any deliveries require different inventory treatment.
Ownership: Policy to prevent in-transit ownership. The easiest form of in- transit inventory to control is when a third party owns it until it arrives at the company’s receiving dock. To do so, have senior management approve a pol- icy preventing any other type of shipping arrangement, and communicate this policy to the staff through a policy and procedures manual, as well as through periodic refresher training.
Mitigation: Verify existence of insurance coverage for owned in-transit goods.
If a company legally has title to in-transit goods, there is a risk that damage to those goods while in transit will result in losses to the company. Thus, the in- ternal audit program should include an annual review of the existence and ad- equacy of insurance coverage for owned in-transit goods. A more passive control is to also include this requirement in a procedure listing all insurance require- ments to be covered as part of the annual insurance renewal process.
Inclusion in valuation: Enforce rapid completion of financials. A common problem is pressure on the accounting staff to delay the month-end cutoff date, thereby allowing the shipping department to pack a few more deliveries into the reporting period to increase revenues. This is an ongoing battle that never re- ally goes away. An excellent control over the issue is to get management so used to receiving financial statements within one day of month-end that they tacitly approve of a stringent cutoff in order to obtain the financials as fast as possible.
Inclusion in valuation: Compare shipping log dates to shipper documentation. A good way to detect an extended period-end cutoff is to compare the shipment date recorded in the corporate shipping log to any shipper documentation on which the shipper records the actual date on which it accepted the goods for delivery. If the shipping staff knows this audit will be conducted, they will be less inclined to stuff more shipments into the reporting period with an extended cutoff.
3-4 Inventory Stocking
Many of the problems associated with inventory originate with the initial deci- sions to set safety stock levels, add product options, and design new components into products. Although these decisions fall outside of the traditional control sys- tems for inventory, they play a key role in the amount of a company’s inventory
investment, and so are included here. All controls noted relate to the addition of stock to inventory.
Additions: Reject all purchases that are not preapproved. A major flaw in the purchasing systems of many companies is that all supplier deliveries are ac- cepted at the receiving dock, irrespective of the presence of authorizing paper- work. Many of these deliveries are verbally authorized orders from employees throughout the company, many of whom are not authorized to make such pur- chases. This problem can be eliminated by enforcing a rule that all items received must have a corresponding purchase order on file that has been authorized by the purchasing department. By doing so, the purchasing staff can verify that there is a need for each item requisitioned and that it is bought at a reasonable price from a certified supplier.
Additions: Revise safety stock levels for seasonal items. The most common ap- proach to setting safety stock levels is to run a historical usage analysis over the past few years and use that information to decide on an average safety stock level.
However, this approach ignores sudden drops in demand caused by seasonality, leaving too much inventory on hand. If demand permanently drops thereafter, safety stock levels will be too high and may represent a risk of obsolescence. A potential control is to mandate quarterly adjustments to safety stock levels of sea- sonal items, thereby more closely matching supply to demand.
Additions: Reduce the number of products and product options. Each incre- mental product that a company chooses to sell requires the storage of more parts.
This is a particular problem if there are many variations on the basic product, mandating storage of each product version. To control the number of these in- ventory additions, schedule a periodic product profitability review and cancel unprofitable products; the determination of unprofitability should certainly in- clude an analysis of the amount of working capital tied up in inventory that is uniquely associated with a particular product.
Additions: Standardize parts. When engineers design new products, they may not consider using existing components. The result is a plethora of similar but separately tracked components, each of which requires some investment in on- hand inventory. An excellent control over these unwanted inventory additions is to require a parts standardization review as an integral step in the development of any new product. To reinforce the concept, consider including the minimiza- tion of the total number of on-hand component parts in the bonus plan of the en- gineering manager.
Additions: Coordinate engineering change orders with on-hand balances. When the engineering staff implements a change order, new parts are added to a product while the replaced items are no longer needed and remain in stock for prolonged periods. In an environment where engineering change orders are common, a nearly mandatory control is to verify the remaining on-hand balance of any components being rendered obsolete, so that the change orders can be implemented in conjunction with the maximum depletion of existing stocks.
Additions: Turn off reordering flags for cancelled components. Many computer systems contain a flag in the item master file, indicating that the system should automatically create a purchase order to replenish on-hand stocks when a min- imum stock level is reached. However, this contravenes a company’s intent in attempting to dispose of any obsolete items, because the system will reorder what is no longer needed. Therefore, a good control is to incorporate in the ob- solete inventory disposition procedure a line item stating that the reordering flag be turned off as soon as an item is declared obsolete.
Additions: Compare open purchase orders to current requirements. The pur- chasing staff may have placed purchase orders that are no longer needed, because the production schedule was changed subsequent to placement of the purchase orders. This problem is automatically spotted by a material requirements plan- ning system, which generates a report listing those purchase orders that should be closed. However, in the absence of an MRP system, a process should be in place to frequently compare open purchase orders to current requirements, re- sulting in the elimination of unneeded inventory receipts.
Additions: Reward managers based on a reduced working capital investment.
One of the classic frauds is to greatly increase the size of value-added on-hand inventory, so that more overhead costs are assigned to the inventory instead of flowing through the cost of goods sold and reducing reported profits. To avoid this problem, an excellent passive control is to include the reduction of a com- pany’s working capital investment in the management bonus plan. By doing so, anyone increasing inventory levels to manipulate profits would end up reduc- ing his profit because of the increased investment in working capital.
3-5 Inventory Storage
Inventory storage tends to be the area in which the most controls are implemented.
Traditionally, the key control targets have been over the loss of inventory through pilferage, as well as the record accuracy for inventory contained within the ware- house. The following list also includes a third category addressing the ownership of inventory contained within the warehouse. Additional controls related to accu- racy levels are described in the “Inventory Transactions” section of this chapter.
Possible controls are as follows:
Loss: Review for case overhang on pallets. Inventory can be damaged if cases are incorrectly stacked on pallets. If they overhang the edge of a pallet, the weight of the stack bears down on the overhanging cardboard walls of the cases, po- tentially causing damage to their contents. A simple control is to include in the cycle counting review a brief visual inspection of the stacking pattern on pallets to see if any overhang is occurring. This review can also be done by audit teams as part of other investigations.
Loss: Restrict warehouse access to designated personnel. Without access re- strictions, the company warehouse is like a large store with no prices—just take
all you want. This does not necessarily mean that employees are taking items from stock for personal use, but they may be removing excessive inventory quantities for production purposes, which leads to a cluttered production floor.
Also, this leaves the purchasing staff with the almost impossible chore of try- ing to determine what is in stock and what needs to be bought for immediate manufacturing needs. Consequently, a mandatory control over inventory is to fence it in and closely restrict access to it.
Loss: Restrict access to dock doors. As just noted, fencing in the warehouse area is an excellent approach for eliminating pilferage. However, dock doors are normally left open during business hours, allowing someone broad access to the warehouse through the doors. To avoid this situation, post “Do Not Enter”
signs near the dock doors and impose a policy of immediately closing all doors that are not currently blocked by a truck.
Loss: Retain expensive items in the warehouse. Although it is much more ef- ficient to store commonly used items in storage locations near the production area, this also makes it easier for employees to steal parts from the more read- ily accessible bins. If there is a history of excessive parts usage from these stor- age locations, consider shifting the most expensive parts back into the more controlled warehouse area. This may call for the use of a formula to determine at what point a part cost is sufficiently low to make it worthwhile to retain in a floor stock location, even with a moderate amount of theft.
Accuracy: Review negative inventory balances. When the inventory record data- base reveals a negative inventory quantity, a transaction error has caused the problem. A good control is to mandate an immediate review of the underlying transactions to determine why the negative balance occurred. This investigation requires an experienced materials management person as well as a computer system that stores a history of individual transaction records.
Accuracy: Pick from stock based on bills of material. An excellent control over material costs is to require the use of bills of material for each item manufac- tured, and then requiring that parts be picked from the raw materials stock for the production of these items based on the quantities listed in the bills of mate- rial. By doing so, a reviewer can hone in on those warehouse issuances that were notauthorized through a bill of material, because there is no objective reason why these issuances should have taken place.
Accuracy: Require approval to sign out inventory beyond amounts on the pick list. If a standard pick list is used to take raw materials from the warehouse for production purposes, this should be the standard authorization for inventory re- moval. If the production staff requires any additional inventory, they should go to the warehouse gate and request it, and the resulting distribution should be logged out of the warehouse. Furthermore, any inventory that is left over after production is completed should be sent back to the warehouse and logged in.
By using this approach, one can tell if there are errors in the bills of material that are used to create pick lists, because any extra inventory requisitions or ware- house returns probably represent errors in the bills.
Accuracy: Use standard container sizes. Inventory counters may estimate the number of parts stored in a container rather than counting each individual item because of the extra time required to make a detailed count. To avoid the result- ing record inaccuracies, consider using standard container sizes, perhaps with an egg crate design in which only a specific number of parts can be held by each container. This approach makes it much easier to determine the exact number of parts in a container. This control is particularly applicable to work-in-process, where standard part sizes are frequently moved between workstations.
Ownership: Segregate customer-owned inventory. If customers supply a com- pany with some parts that are used when constructing products for them, it be- comes easy for this inventory to be mingled with the company’s own inventory, resulting in a false increase in its inventory valuation. It is certainly possible to assign customer-specific inventory codes to these inventory items in order to clearly identify them, but a more easily discernible control is to physically seg- regate these goods in a different part of the warehouse.
Ownership: Segregate supplier-owned inventory. Some suppliers retain owner- ship of their goods at the company site until the goods are used in the production process, at which point they bill the company for their use. A common control is to lock down access to this inventory, so that only an authorized person can both access it and log out items used. An alternative control if the supplier- owned inventory is extensive is to assign sole control over this inventory to an on-site supplier representative. Another variation is to position this inventory in an adjacent warehouse, from which deliveries can be readily made to the com- pany while control over the inventory is more easily assured.
3-6 Off-Site Inventory Storage
When there is not sufficient on-site space available in which to store inventory, it is typically kept in storage trailers or leased off-site premises. One control issue is the loss of inventory in these locations, because access to the inventory may be less secure than in the main corporate warehouse. Another problem is the accuracy of inventory records in the off-site locations. Both control issues are dealt with through the following controls:
Loss: Access control. When seasonal demand forces inventory levels higher than the storage capacity of the main warehouse area, overflow stocks must be stored elsewhere, possibly in locations having less restrictive access controls.
Consider as the best alternative the use of a third-party warehouse with full ac- cess controls. If not available, at least lock down access to any additional rented space. If storage trailers are used for overflow storage, be aware that an entire trailer can easily be stolen, so fence off all storage trailers and lock the gate.
Accuracy: Include off-site inventory counts in the closing procedure. A com- mon problem is not including in the month-end inventory the inventory counts for off-site storage locations, resulting in an excessively large charge to the cost