OTIF combines two questions into one number: did the delivery arrive when it was supposed to, and did it contain everything that was ordered? An order that is on time but short, or complete but late, fails. The basic calculation is the number of orders delivered on time and in full, divided by the total number of orders, for a given period.
The details matter. Buyers define OTIF differently: by order, line or case; against a ship date or an arrival date; and with or without tolerance for early deliveries. Retailers often build OTIF into their vendor compliance programs and charge fines when a supplier falls below target, so suppliers need to know exactly which definition each buyer applies.
Many OTIF failures start with data rather than trucks. A PO acknowledgment (EDI 855) that confirms the wrong quantity, a date change nobody recorded or a late ASN (EDI 856) can all put an order on the wrong side of the measure. That is why OTIF is usually tracked alongside perfect order performance on a supplier scorecard.