Balancing Inventory Turns & Customer Service

Norco's Central Warehouse

Inventory stored in product bins at Norco's central warehouse in Boise, Idaho.

Many distributors are finding themselves very wary of borrowed money and looking for ways to bring cash back into the organization. The biggest cash asset in a distributor’s business is inventory. This appears to be the logical place to start shoring up the reserves. I would definitely encourage distributors to look at prudent reductions in inventory. Most distributors hold at least 30 percent more inventory than necessary to keep up with current customer demands. It is the panic-based reductions that I want to caution distributors against.

Inventory seems to be the prevailing metric associated with a healthy organization. The conventional wisdom appears to say that the faster you turn the inventory, the better you are. In fact, many organizations have developed incentives based solely on turning the product. While turns should be part of a compensation strategy, it can’t be the only thing you measure.

Inventory Turn Calculation
Inventory turn is a measure of how well your inventory investment is performing financially. To determine the inventory turn in your business, take the annual cost of goods sold from stock sales and divide it by the average inventory value. One of the most important words in that formula is “STOCK” from “stock sales.” This is where I see the greatest confusion when distributors calculate this metric. They tend to throw all sales in the numerator of the equation. When you include a drop ship into the measurement, are you really measuring the performance of your money? Did you invest your money to hold that item in inventory? Of course not. The inventory was held at the supplier’s facility. This logic holds true for non-stock specials that you buy for a customer. Transfers to fulfill a customer order are often included in the inventory turn calculation for the selling location. Should they be? When you are determining the performance of inventory in a certain branch, they should be excluded. Again, you are not using the inventory of the selling branch; you are capitalizing on the assets of the shipping branch. You can see how the numbers can be fairly skewed. This is why I am very skeptical when I see industry averages.

How sure are we that the other guy did the math right?
If my compensation was based solely on inventory turns, I could easily achieve the goal. The fastest way to increase inventory turns is to reduce the average inventory value. If you want to reduce inventory, quit cutting purchase orders. Believe me, you would bring that average down in short order. Unfortunately, it would also have severe consequences on your sales figures – but that isn’t what you are measuring. Can anyone see the danger?

I am very concerned that distributors may be leaning toward a wholesale slashing of inventory values in order to preserve the cash. Things like buying budgets and buying after the 25th of the month might be coming out of the closet. These are dangerous practices that focus on short term gains and create long term problems.

If there were 10 lines on a customer order, and you were able to ship 8 of those lines complete, you achieved an 80% customer service level.

If you want to reduce inventory value, take a hard look at the dead and dying inventory. Get rid of the inventory that no one seems to be interested in. Be very cautious when a supplier suggests that you need to carry the whole breadth of the line. Look at your safety stock levels on the least popular items. Breadth of line is ok, but don’t allow depth in the less popular items. As I mentioned earlier, the wholesale reduction of purchase orders will have negative consequences. Without inventory on hand, your customers will see you as an unreliable supplier. This is why you must measure your customer service level in conjunction with the inventory turns. It is not good enough to just put inventory in your warehouse. You need to bring in the products your customers want. More important, you need to bring the products in when your customers want them. Meeting your customer needs is what the customer service metric is all about.

Measuring Customer Service
The formula for measuring customer service is this: Take the number of lines (on customer orders) shipped complete divided by the number of lines ordered. This is a fairly strict measurement of how well you met the customers’ needs. If a customer orders 10 grinders and you have 8 in stock, you ship the 8 and back order the other 2. What is the customer service level on this line of the order? Many would argue that it is 80%. Wrong. It is 0%. You failed to meet the request of the customer. The customer wanted 10 and you gave them 8. If they wanted 8, they would have ordered 8. Think of measuring the customer service performance by the order. For example, if there were 10 lines on a customer order, and you were able to ship 8 of those lines complete, you would achieve an 80% customer service level for that order.

Seems a bit harsh, doesn’t it?

Let’s put this another way. Say you stick your ATM card in the bank machine and request $100. The machine spits out $80 and tells you to come back tomorrow for the other $20. Eighty percent isn’t bad, right? You only have to wait a day for the remainder. Are you satisfied with this transaction? I have a feeling that some of you would let your frustration be known to the little camera in the ATM.

Now that you are measuring customer service percentages, what is the goal? I typically like to see distributors shoot for an overall percentage of 90-95%. Anything higher than 95% would force you to invest a ridiculous sum of money in your inventory. You probably don’t have the space to achieve a 96% or higher. This is an overall inventory percentage. Some items will be higher than 95% and others will be lower than 90%. Here is a great way to use this measurement: Make sure that your most popular items, the top 5% your customers expect you to have, are in the 99-100% range. This will give you the appearance of having everything when they need it. As the popularity drops, the customer service percentage can drop with it.

When you are measuring a vendor line, watch out for an overall service level in the low 80%.This means that you are carrying too little inventory, or you may simply be carrying the wrong inventory. Go back and review the hits ranking to see which items are most and least popular. Adjust your levels to get the customer service percentages in line.

Turns and customer service are the balancing act that all inventory managers must face. If you try to spin the inventory too quickly, you will develop holes in stock. Back orders will occur and your customer service will deteriorate. Let it deteriorate too far and the phone will stop ringing. Conversely, when you tip the scales too far toward the customer service side, your turns will reduce and you will be forced to borrow more. One side cannot exist independent of the other. In uncertain economic times, the distributor who balances inventory asset will be in better shape long term than the organizations that panic and make short-term decisions.

Gases and Welding Distributors Association
Jason Bader Meet the Author
Jason Bader is managing partner of The Distribution Team located in Portland, Oregon, and on the Web at, which specializes in helping distributors become more profitable through operating efficiencies.
    Where's The Money
    Robotics 101

    The Pitfalls of Social Media

    Balancing Inventory Turns And Customer Service

    Shale! Shale! Shale!

    Liquid Natural Gas Distribution

    Watching Customers In Action

    Technology Claims The Collections Beast