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First Thoughts
  By Dan Gilmore - Editor-in-Chief  
     
   
  July 30, 2009  
     
  Readers Respond: Measuring Inventory Performance  
 


Again this year I am biking across the state of Ohio, and am using that opportunity to let SCDigest readers carry the burden for this week’s column.

 

A number of weeks ago, I did a column on “Measuring Inventory Performance.”

 

It was really just meant to be a preliminary column to a subsequent one that would outline my thoughts in more detail. Nevertheless, we received a significant amount of reader feedback; we’ve had columns in the past that generated more, but I don’t think ever of this total quality. This week, I am sharing some of the highlights – am quite confident you will enjoy them.

 

David Gustin of Global Business Intelligence said that “This is a very complex journey you have embarked on Dan.” Why? In part because “CFOs and Treasurers of corporations are increasingly becoming responsible for “Supply Chain Finance” solutions, yet there is a general confusion as to how SCF works and the role of different players.”

Joseph Barnes Says:

Inventory is like any other “asset” which has to generate a return. I like to look at inventory as a portfolio of assets, each generating a return to shareholders.


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Reader Feedback


He also observes that “functional conflicts exist within companies due to different success factors for Procurement (obtain best price), Finance & Credit (increase DPO, reduce DSO, focus on buyer risk and maintain liquidity), and Sales (sell more and extend terms if need be). These are not easily resolved.” I guess we could say Sales, Inventory and Operations Planning (SIOP) is a tool to manage these trade-offs, but most are still very early in that venture.

 

Fred Schafer of Trane opined that “the best measure for inventory management/planning is Days Forward Inventory (DFW), or inventory/(forward sales forecast/days in forward forecast period). The forward forecast period may be set to reflect what is most meaningful for the respective business/need."

 

Why a forward forecast as the denominator? Because, Schafer said, “inventory is in place to satisfy forward demand.”

 

He adds “Another set metric is the “quality” of inventory. This is more about the make up of the inventory and readiness to serve.  There are three: (1  available to commit inventory;  (2) categories of inventory [which he explains as basically a categorization of inventory by status]; and (3) SKU level/ mix performance [how close SKU inventory levels are to targets].”

 

Joseph Barnes of Orco Construction Supply says that “Inventory is like any other “asset” which has to generate a return. I like to look at inventory as a portfolio of assets, each generating a return to shareholders. That return is based on a number of different factors, including how often it sells, the gross margin it returns, the cost for holding it, buying it and moving it along with some expectations on shelf-life. By looking at inventory this way, it basically equalizes across industries what the true value of inventory is for the investor."

 

David Armstrong of Inventory Curve agreed with my point that there are often definitional problems with how we calculate some inventory measures – even something as simple as “turns.”

 

“The complications mentioned in the article include calculation of average inventory along with use of cost of goods sold versus sales revenue to calculate turnover,” Armstrong says. “The reality is that there is not a single, defined standard method for either of these, so one must be careful in reviewing data to try to understand exactly what is being calculated and how.”

 

Daniel Araujo from Brazil’s DAC & C also notes some challenges in the area of measuring “turns.”

 

“I prefer to calculate either Turns or DIO (Days Inventory Outstanding) at an aggregate level using the value of inventories and the cost of goods to be sold. Using revenues (with profits and sales, administration, distribution and advertising expenses) distorts the performance of the inventories,” he wrote. He added that “At the item level, where good or bad management of inventories really needs to happen, units instead of $ is the most appropriate. If you calculate aggregate turns, including profits and expenses and item level turns in units, you will never be able to reconcile management policies and planners' actions.”

 

Bob Belshaw of GE Capital says getting to inventory measures that are most meaningful to CEO/CFOs is critical.

 

“The impact of decisions made around inventory policies, including strategies like JIT, VIM, timing of title change and the newly packaged financial products that target supply chain finance require significant thought and discussions,” he wrote. “I have come to believe the power of using the CFO metrics is that the organization begins to find a language to communicate in that is understood in the C-levels and on Wall Street,” adding that often, in his view, the impact of inventory on key corporate financial metrics “has gotten to senior leaders in our supply chain and procurement organizations.”

 

I also really like what Dwayne Wildhagen of Springs Window Fashions had to say about looking at inventory and demand.

 

I believe the best measure of inventory performance is to compare average inventory over a period of time (typically monthly) to the inventory consumption over the same period of time,” he wrote. “This is the only "true" measure in my mind because it removes all the other variables contained in COGS, so it is a true reflection of how well your inventory is "turning" or being managed.” Like Schafer, he prefers a more forward looking view, “because we are not bringing in inventory to support last month's sales, rather next month's sales.”

 

Jennifer Vaughn of private equity company American Capital says inventory management effectiveness is key to the success of the company’s they invest in and that the tool they prefer is the Inventory Quality Ratio (IQR). We’ll cover this in more detail in a future column, but, in summary, IQR looks at inventory levels versus targets for different SKU velocity categories (e.g., ABCD), and at levels of slow and obsolete inventories, all of which results in a “score,” with 100 being a perfect score.

“IQR is a better metric of inventory performance than either turns or DIO because it is based on future demand, provides a performance measure for each segment of the inventory, and shows you where you can actually take action to reduce excess inventories, free-up working capital, etc.,” Vaughn says. She adds, “It has opened our eyes to better ways of managing one of our largest balance sheet items – Inventory.”

Brian Coats of Carrier agrees. “Inventory metrics which fail to address the usability of on-hand inventory are insufficient in measuring the true value of what is in stock. Inventory Turns and DIO both are inadequate in that they do not take into account the usefulness of the inventory on hand,” he wrote. “With IQR, Carrier has been able to quickly monitor performance at individual factories and identify opportunities for improving Inventory Performance.”

I could add lots more, but am out of space. As always, I am simply impressed with the collective knowledge and wisdom of SCDigest readers. Thank you.

What is your reaction to the feedback from SCDigest readers on Measuring Inventory Performance? What would you like to add? Let us know your thoughts at the Feedback button below.

 
 
     
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Feedback
2009-07-31

July 31. 2009

Your readers responded rater simplistically to a complex problem.

The inventory management problem is a balancing act, as tradeoffs have to be made continuously. A single measurement will not resolve the inventory problem.

Over many years I have developed a simple set of measurements that describes the inventory problem.

-- Customer service: the number of orders you managed to fulfill perfectly

-- Inventory turnover rate: then churning rate of inventory

-- Cost of keeping inventory: all cost of ordering, storing and distribution

As these measurements are interrelated, it forces the Inventory Manager to look at all three aspects. A single measurement skews the focus in one direction only and may cause irrational, functional behavior.

As these measurements are ratios, it enables meaningful comparison between different periods. The measurements should be measured on a trend basis, as statistical fluctuations will occur.

Jan de Ruyter
Magistix
Pretoria, South Africa



2009-07-31

July 31, 2009

Just a quick thank you to for sharing these feedback comments - very thought provoking and timely as our organisation heads towards two key events this year, i.e. 2010 Budget (in which I have to reset our Group and BU inventory targets, aggressively!; and process-mapping/kpi measurement stage of an ERP implementation).

Methods of inventory performance measurement are as many as the proverbial 'how long is a piece of string'- and Joseph Barnes' succinct comment that each 'portfolio' of inventory has to generate its own return is a good principle to start the internal discussion and analysis!!

Roger Sanderson
Group Director, SCM
Esquel Enterprises Ltd.



2009-07-31

July 31, 2009

Inventory is the thing that we have to sell to our customers to satisfy their needs and to make money.

From a pure supply chain point of view measuring inventory performance can be done as others have pointed out using a variety of measures - inventory forward cover or turns are 2 of the many already mentioned.

Each of these measures will show how much inventory we have to cover future sales. However from the financial perspective inventory is a cost that ties up cash and is only useful when it is sold and realises a value. It can also be used to recover fixed costs in a manufacturing facility when the facilities are underutilized and so making stock helps to reduce cost per unit made.

All of the above are legitimate measures of inventory performance. The most important measure for me is how much inventory did you make relative to your plan? Inventory is an outcome of your decisions about service level, manufacturing performance and lead times. It is affected by the variability in demand and the variability in supply plus a few other factors.

Starting with an organisation's strategic decisions and the consequent budget we can calculate how much inventory we need, we can support, we want or we can make. These decisions are made at business S&OP meetings and form a communication to the organisation as an inventory plan.

ideal measure of the success of our inventory performance then becomes - did we make what we said we would make? Did we sell what we said we would sell? Therefore did our inventory end up as it was planned to?

Geoff Walker
General Manager Supply Chain
OneSteel



2009-07-31

July 31, 2009

I believe Joe Barnes' broad treatment of 'inventory as an asset' is right on the money.

As for measuring inventory performance, there is no single metric. We promote a balanced scorecard approach with the following four metrics:

-- Inventory to meet Service Level expectations of the customer (requires that you know what your customer expects in terms of response time and availability)

 -- Inventory investment in the supply chain (average forward-looking DOS or Turns that is tied to above SL metric). The Higher the expectation of the customer in response time and availability, the higher the inventory.

-- Margin contribution of inventory (Gross Margin Return on Inventory)

-- Gross Margin in Sales/Avg Inventory Investment (This goes to the heart of the premise that inventory has to be seen as both an asset and a liability, and the corresponding question of 'what is the right SL to maximize my return on inventory investment?' In general, high-margin products can stand to have higher Service Level targets and inventory investment, with a point of diminishing/degrading return on margin with each incremental investment in inventory.

-- Expediting Costs related to having the wrong inventory of the wrong type/amount at the wrong place.

You do not want to blow out your transportation/expediting costs in order to minimize inventory holding costs. It is possible to provide a real business scenario in which you can do well in any one/two/three of the above metrics by blowing out the other metric(s).

Omer Bakkalbasi
Principal
CHAINalytics



2009-07-31

July 31, 2009

What Joseph Barnes says is a 'big truth.'

We understand this concept from 10 years ago, but only in the few years ago the logistics community began to see something like that 'inventory = asset.'

Ruben Sessa
Director
Ideas y Tecnologia
SA



2009-07-31

July 31, 2009

For finished goods I like to use Gross Margin Return on Inventory Investment ((Margin % * (Sales/AvgInvCost)) - Using 3.2 as the breakeven highlights where margin is not covering total costs of carrying the inventory.

For raw materials I use a simple consumption/average inventory turns ratio.

Richard W. Herrin
Global Sales, Operations, and Inventory Planning Manager
Tredegar Film Products



2009-07-31

July 31, 2009

Interesting piece on inventory. I like the concept of IQR.

When working in the UK I became responsible for a small group of inventory planners alongside some general distribution responsibilities (including tracking the distribution KPIs). We had a lot of low value fast moving items in the range.

When inventory management was under the responsibility of the purchasing side of the business the focus was on financial value and 'turn' not too much attention was paid to detailed availability. I removed 'financial value' from the focus entirely and determined to drive up availability and line fill as this was hurting customer satisfaction.

So we focused on ABC velocities especially 'frequency of pick' (more correctly how often an item appears on an order line). This produced for us a relatively short list of 'Super A items' (150 out of about 5,000) and a very long tail of 4,000 or so where inventory levels were way too high.

We expedited the A lines, worked with purchasing to get more frequent deliveries, smaller load sizes and shorter lead times and all the other good stuff we read about so often. We got full truck load discounts from 2 or 3 key vendors for 1 delivery a week -- when some of them had dedicated multi-drop trucks in our area 3 times a week.

By putting our volume on the dedicated multi-drop the vendors agreed to five deliveries a week on a 2 day lead time. Their other customers in our area got a service increase too! We ramped up the turn on some key lines by bringing in 2 or 3 deliveries a week that were close to the volumes sold. We didn't know it at the time but we had a demand driven supply chain!

The net result was within a matter of weeks we increased availability (up from 90% to 96ish) and line fill went up from 94-5% to 98-99%. Not much by today's standards but for the time and in that industry it was close to best in class. We ignored the financials but the above effort reduced the value of inventory by GBP4m (not bad for a less than $60mm business).

We also reduced the shipment costs of all the back orders for those low value fast movers too.

This was of course measured by finance as savings in the carrying cost expressed as a % of $4m. But I liked to think that we gave the cash flow a $4mm boost over a period of only three months or so.

In today's economy a lot of businesses could probably do with that same boost.

Nick Turner
Senior Prod
uct Manager, Execution Solutions
Sterling Commerce





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