Why Does System Inventory Differ from Reality?

An inventory difference is not one number. It is the effect of movement recorded late, against the wrong document, or not recorded at all. It may be a partial receipt, an issue without an order, or a transfer the receiving location never confirmed.

Separate movement into receipt, issue, transfer, reservation, return, and adjustment. For each type, define who creates the document, who executes it, who reviews it, and when available stock should change.

Reservations create particular confusion. Physical stock may exist but be unavailable to a new order. If the system does not distinguish on-hand, reserved, and available quantities, the same stock is promised twice and the problem appears during fulfilment.

Returns need clear states as well: received but not inspected, accepted back into saleable stock, or damaged and awaiting adjustment. Adding every return immediately creates false availability.

Do not begin with one broad adjustment that hides the cause. Select fast-moving items, trace recent movement, and compare document time with physical action. Correct the rule and access first, then count again.

The goal is not zero differences for one day. It is a workflow that makes every difference explainable and reduces recurrence.