Fill rate used to be the question. It isn't anymore, and the CPGs who haven't caught up to what retailers are really measuring now are quietly losing sales they can't see.
For a long time, the question retailers asked their suppliers was a supply chain question. Did the cases show up on time? Were they in full?
Over the past decade, fill rate / OTIF (on-time, in-full) became the language of supplier excellence. They were tracked consistently, fined against, and even reported up to the board. If your numbers were green, you were doing your job as the supplier.
Hitting those metrics consistently still matters today, but it is no longer enough. Retailers have moved on to a harder question, and most suppliers are still catching up.
The new question is simple to say and hard to deliver: can a shopper actually buy your product, when they go looking for it?
Walmart, Target, Kroger, and others have all started to move in this direction, each with their own specific metrics. The terminology varies. The standard doesn't. A product is no longer judged on whether it left your DC. It's judged on whether it's purchasable in the moment that matters, when a shopper is standing in the aisle looking for it.
The reason for the shift is the shopper. Out-of-stocks continue to cost the global retail industry an estimated $1.2 trillion in lost sales every year, and only about 45% of that demand stays with the retailer. The rest substitutes, switches, or walks away. Retailers learned the hard way that a perfect OTIF score doesn't protect them from any of that. A truck can arrive on time and in full, and the product can still be missing from the shelf when the shopper goes looking for it.
Fill rate measures what happened at the back door. Purchasability measures what happens at the moment of truth.
This is the gap most CPGs underestimate. To be truly purchasable, a product has to clear three conditions on the shelf:
Each of those conditions can break for different reasons, and that's exactly why purchasability is harder to manage than fill rate. It's the outcome, not the input, and reading it well means understanding the signals underneath it. Two of them stand out.
The first is Zero Sales. It flags stores where an item should be selling, based on what comparable stores are doing, but isn't. The product is in the system. The velocity isn't. That gap almost always points to misplaced product, planogram non-compliance, or an early out-of-stock the inventory record hasn't caught up to.
The second is Phantom Inventory, and it's the inverse. The system shows units on hand, but sales have flatlined. That pattern points to shrink, scanning errors, or product stranded in the wrong aisle, and it requires a store-level intervention.
What makes both signals so valuable is that they're invisible to OTIF. Which means a supplier watching only its fill rate has no way to see them, let alone act on them, until the lost sales have already added up.
This shift didn't start with metrics. It started with the shopper, and the metrics are retailers catching up to what's already happened on the floor.
The shopper who would walk three aisles over to find your product, or come back tomorrow, or ask an associate, that shopper is gone. Today's shopper has a private label option two feet away, a competing brand one click away, and roughly zero patience for a search. When the product isn't where it should be, only 45% of that demand stays with the retailer. The rest moves on, and a meaningful share never comes back.
That's the real reason fill rate isn't enough anymore. OTIF was built for a world where getting the product into the building was the hard part. The hard part now is the last fifty feet, and the shopper has stopped giving brands credit for the first thousand miles.
