The Supply Chain Planning Problem Behind Your Inventory

Walk into a warehouse that is heavy on stock and you are looking at the result of decisions made weeks or months earlier. That is the view Neil Marchant, founder of MET Supply Chain Consulting, has formed over 25 years planning supply chains for some of the world’s largest consumer goods manufacturers.

In a conversation with Moddule’s co-founder and head of sales, Ben Jones, Marchant described how what most think of as inventory problems are actually planning problems, and they start with data and demand signals.

1. Your inventory is a record of your planning decisions

Most businesses treat excess stock as a warehousing issue to be managed, while Marchant sees it as evidence. Everything sitting on the shelves is the output of choices made upstream by the planning team. When a distribution center is full of product the retailer won’t take, the cause is not the warehouse. It is the forecast, the production call, and the buying decision that put it there.

"Inventory arrives one planning decision at a time."

The trouble, Marchant says, is that manufacturers feel the symptoms without connecting them to the source. They see cash tied up, outside storage filling, shortages in the lines that matter, and relationships with retailers under strain. What they rarely do is trace that whole cluster back to a single decision about how they plan.

2. The demand signal decides everything downstream

Most manufacturers plan from their own invoice history, what they sold into the retailer in the past, and project it forward. The problem is that invoice history tells you what was ordered but nothing about why, so planning becomes guesswork, and guesswork gets covered with buffer stock.

The alternative Marchant works toward is consumer-led: plan from what shoppers are actually buying through the retailer, and from the inventory the retailer is holding, so you can see a replenishment order coming before it lands. He frames the difference with two manufacturers facing the same jump in a retailer’s order. One reacts blindly and builds more buffer. The other can see that consumer sales only grew a small percentage, so the retailer is about to be overstocked, and plans accordingly.

"One is based upon a knowledge of what’s causing the retailer to place those orders in the first place, and one’s based upon guesswork as to why the retailers place that order."

3. Technology is only as good as the signal beneath it

Marchant is optimistic about what modern systems and AI can now excel at, which is crunching the numbers at scale and surfacing the items that actually need a planner’s attention this week. Most powerful of all is a metric most manufacturers don’t have visibility into: the retailer’s future inventory response, plotted forward so you can plan rather than react.

But he is careful to clarify that speed and algorithms do not fix a flawed foundation. If the demand signal underneath is wrong, technology just gets you to the wrong answer faster.

"It’s still just using the wrong demand signal and guesswork with a fancy overlay."

The human stays essential, adding the context and judgment the AI model cannot. Technology sharpens good planning, but it doesn’t replace the decision about what to plan from.

Watch the full conversation with Neil Marchant on Moddule's YouTube.

If your inventory is telling you something about your planning, talk to the Moddule team about what it would take to act on it.