What is stock cover and why it lies on perishables
Stock cover is how many days the current inventory lasts at today’s sales rate. Five hundred units selling fifty a day give ten days of cover.
Don’t confuse it with turnover. Turnover looks backward and counts how many times stock cycled in a period. Cover looks forward and projects how many days remain until you hit zero.
How the operation measures it
The math is current stock divided by average daily sales. The system computes it per SKU, per store, per day. The buyer uses the number to decide when the next order has to land.
Anyone who has worked the operation knows cover is the ruler the buyer watches most. It looks objective. In dry grocery, it is.
Where it lies on perishables
Cover assumes two things: that sales are linear and that the product never spoils. Both break in produce, in chilled, in the bakery.
Seven days of cover on a yogurt with four days of shelf life is not slack. It is shrink already on the calendar. The number says “stock for the week”; the expiry date says “half of it becomes loss on Thursday”.
The average hides this. A chain can show healthy aggregate cover and lose 8% of perishables to expiry every week. The truck arrives full and leaves full, except part leaves for the bin.
The rule changes by category. Bananas and UHT milk show the same cover on the dashboard and share nothing in real life.
Why this changes an AI project
A perishables forecast does not optimize cover. It optimizes sales within shelf life. Those are different objectives, and confusing them means you buy well and lose at the shelf.
A model aiming for constant cover will overstock what spoils and run short on what sells fast. The right criterion crosses shelf life, day-of-week sales curve, and acceptable shelf-out. It is the same aggregate reading that misleads in MAPE and in DSI.
This is the kind of decision we deliver written down, not guessed daily.
Look at the average cover of your perishables section and the expiry shrink for the same period. Do both numbers coexist? Then the dashboard is calm and the operation is leaking.
Think about the term each area of your operation uses but defines differently. Here it is usually “healthy stock”. Tell me yours. In one hour I will send back a one-page card: the formula, the measurement points, what the number actually means, and where it misleads. If the card shows the replenishment system has to be rebuilt, the two-week Diagnóstico is the next step.