Body of Knowledge

Over the years as I have worked in the field of supply chain with broad interests specifically related to inventory, operations, materials and systems as well as the other functional areas; I've discovered new ideas, concepts and practices that extend the body of knowledge.

I'm particularly grateful to the many members of the Council of Logistics Management (now the Council of Supply Chain Management Professionals) who were willing to mentor and freely share their knowledge with me.  

To that end, I hope that publications on this page are valuable to you and extend the body of knowledge.  I expect to add more in the future.

Sharpening Inventory Management

In 1985, I was honored to have an article on my work in inventory published in the Harvard Business Review.  The article is no longer available as a reprint, but you can view by clicking on this link, Sharpening Inventory Management.

Using GMROI to Evaluate Purchasing Quantity Price Breaks 
explores the relationship between cost and profitability using Gross Margin Return on Inventory Investment (GMROI) with a surprising result: in many cases, getting a lower cost comes at the expense of higher order minimums which translate to lower turnover and as a result, yield a lower GMROI. This means that the higher margin obtained through a lower cost is more than offset by the lower inventory turnover. For more information on GMROI, see the GMROI page on this website. 

NOTE:  The GMROI Lot Size Calculator is a spreadsheet designed to supplement this publication. It is available in the On-line Store.

Using Safety Time as an Alternative to Safety Stock
provides a method that can reduce inventory investment and improve overall turnover without compromising service.  The report looks at trade-offs between the two approaches, how to use safety time and provides a enhanced version of the traditional average inventory formula if safety time is used.  

If you would like to discuss assistance with applying these or other supply chain concepts and ideas within your organization, please feel free to contact me at

David Armstrong, Principal

 ®   Inventory Curve, LLC, Westminster, Colorado USA

Real Time Analytics

Website Builder