Continuous quality testing
Continuous testing of transmission times for international priority/airmail letter-post items was developed in order to provide designated operators with a simple, effective tool for measuring international quality of service.
The main characteristics of the testing are:
- the tests are of the "end-to-end" variety (test letters posted in letter boxes and delivered to test participants);
- data on posting and delivery are processed separately and are only merged by the independent body (the International Bureau);
- the testing is continuous (the test letters are posted continuously, six days a week);


