The SAME project for "Support the Adoption of Metrics for Email" is an DMA’s EEC initiative aiming "at creating a standardized framework for the reporting of email metrics across the industry".
The goal is to establish and define standard email metrics and to have all email metrics reported by ESPs the same way. It may allow marketers to make apples to apples comparisons between ESPs.
In 2010, the EEC has defined and published proposed email metrics:
inbox placement rate
confirmed open rate
email render rate
average recipient render rate
click through rate (CTR)
click to open rate (CTOR)
ESP adopting those metrics and being audited may display the email measurement seal.