On July 5, 2018, the Postal Regulatory Commission approved Internal Service Performance Measurement (SPM) for USPS® as the official system of record for service measurement and reporting effective October 1, 2018. This means USPS will retire the legacy External First-Class Measurement system on September 30, 2018.
Internal SPM leverages the USPS workforce to randomly scan live mail at collection and delivery points, and combines this data with billions of pieces of live mail processed in the USPS network. Internal SPM provides a more robust and representative reflection of service performance, which not only benefits USPS internal operations, but also increases mail visibility for our customers.
The information obtained through Internal SPM provides invaluable diagnostics to identify root causes for service failures and the opportunity to improve service. Delivering on our service commitment to our customers just makes sound business sense.
— Corporate Reporting, Enterprise Analytics, 8-16-18
Source: USPS
Related: USPS: Internal Service Performance Measurement (SPM) will replace External First-Class (EXFC)