A transparent metric is one for which the claims of specific properties or capabilities for the metric are substantiated and open to independent verification. 
This includes the user having the opportunity to know the limitations, construction, and sources of data for the metric. 
Examples of transparent metrics are audience measurement ratings audited by the Media Rating Council such as those from Nielsen’s National TV Audience Measurement service. 
The alternate audience-based movie rating system deployed by IMDb is an example of a non-transparent metric. 
Transparency is one of the 10 Characteristics of an Ideal Metric designated by the Marketing Accountability Standards Board.
- Accountable Marketing: Linking marketing actions to financial performance, 1st Edition; Eds. Stewart, David W. & Gugel, Craig; Routledge, 2016.
- Universal Marketing Dictionary Project, 2023.