Walk any inventory process and ask three questions at every step where something moves. Which item is this, and how do we know? How much of it is there, and what measured that? Who did this, where, and when?
Identity
Read off the item - a QR mark or an RFID tag. Not recalled, not inferred from position, not read from an accompanying piece of paper.
Quantity
Measured by an instrument: weight, dimensions, temperature, humidity. A count performed by a person is an estimate wearing a number’s clothing.
Context
Supplied by the device, not the operator. Location, identity of the person, time, and the state of the ERP transaction the reading belongs to.