Postal services - Quality of service - Measurement of loss and substantial delay in priority and first class single piece mail using a survey of test letters
This document specifies methods for measuring the level of loss and substantial delay, using a surveyof test letters, of domestic and cross-border priority and first class single piece letter mail, collected,processed and distributed by postal service operators.It is impossible in practice to distinguish between items which will never arrive and items which havebeen delayed for a very long time. A minimum period is therefore defined after which an item that hasbeen sent shall be treated as if it has been lost or substantially delayed for the purposes ofmeasurement.The resulting overall figure for loss and substantial delay is to be expressed as a percentage