Shelf availability is measured automatically by comparing the number of products present on the shelf against the number expected to be there, expressed as a percentage 1. The formula is OSA (%) = (Number of SKUs available on shelf ÷ Total listed SKUs) × 100, which gives a single figure at SKU level 1. On-shelf availability is distinct from stock availability: stock availability describes whether inventory exists in the system or the store, while on-shelf availability describes whether that inventory sits on the selling shelf where a shopper can reach it 1.
Data sources that feed the measurement
- Inventory systems track sales promptly, and inside Walmart's Retail Link suppliers can view on-hand units in store to help determine whether an item is out of stock 2.
- System data alone produces phantom inventory, where the record shows units in stock yet a SKU goes weeks without selling in a single store, which is typically a good indication the item is out of stock 2.
- Mobile audit tools let field teams record missing SKUs, flag empty facings and capture replenishment delays during a store visit, shortening the gap between detection and corrective action 1.
- Store intelligence technologies including AI and ML, IoT sensors and shelf-edge cameras have delivered significant benefits to US retailers, according to a March 2024 report from Coresight Research sponsored by Simbe 3.
Why automation is used
Manual processes on their own cannot provide real-time shelf visibility across multiple stores, which is why technology carries the measurement 1. The stakes are commercial: of surveyed consumers, 12% said they would switch to a competitor's product when an item is missing, and 32% said they would leave without buying anything 2.