What is Purchase order (PO)?

A purchase order (PO) is the document a hotel issues to a supplier confirming what it is buying, in what quantity, at what agreed unit price, and on what delivery terms. It is the “what was ordered” in a 3-way check, and it is the moment the hotel states a price before the supplier states one.

The baseline every invoice is measured against.

A PO does two jobs. Before the goods move, it is where approval and budget checks happen — someone decides that this spend, at this price, is acceptable. After the goods move, it becomes the reference point the invoice is compared to.

Without one, every invoice is a judgment call. The only available baseline is whatever the last invoice happened to say, which means a price that crept up quietly becomes the new normal simply by being printed twice.

A worked example.

At a Niagara Falls hotel, a house blend coffee line moved from $160.50 to $211.69 — a 31.9% increase on a recurring order nobody re-approved. The item was the same. The supplier was the same. The order was a standing one.

With an agreed PO price on file, that invoice arrives as an exception the day it lands, with $211.69 sitting next to $160.50 and the variance already calculated. Without one, it arrives as a slightly larger coffee bill in a month when a lot of things cost slightly more.

Purchase order, standing order, blanket order.

A purchase order covers one delivery. A standing order repeats a fixed list on a schedule — the linen run every Tuesday, the milk order every other day. A blanket order agrees a price and a volume commitment up front, then releases quantities against it over months.

Hotels lean heavily on the last two, because daily operations do not have time to raise a fresh document for every case of napkins. That is reasonable. The trap is that a standing order tends to lock in the quantity and let the price float — which is precisely backwards for anyone trying to control cost.

What usually goes wrong.

• Orders are placed by phone, text, or a supplier portal, so no PO is ever produced
• Standing and par-based reorders repeat forever without anyone revisiting the price
• A PO exists but carries only quantities, not agreed unit prices — which makes price drift invisible
• The PO is raised after the invoice arrives, to satisfy a process, and simply copies the invoice
• The pack size on the PO and the pack size on the invoice are not the same, so the comparison is not like for like

What a purchase order does not do.

Raising a PO does not stop a supplier from billing something else. It creates the evidence that they did. The document has no force on its own — it only matters if somebody, or something, compares it to the invoice that follows.

What Atrium does about it.

Atrium compares purchase orders, receipts, and invoices line by line and flags every unit price billed above the order. Where a hotel does not raise formal POs — which is most independent properties — Atrium uses the item’s own price history as the baseline instead, so a recurring item that moves gets caught either way.

That is the mechanism behind supplier price drift tracking, and it runs alongside the other checks in hotel procurement software.

Two related terms: the goods receipt is the other half of the comparison, and pack-size normalization is what keeps a PO price and an invoice price comparable when the case size changes.