go to the Mastery Gradebook where all the colored boxes indicate (usually) a decaying average per student per Outcome,
click on the colored box,
and see a pop-up with the trend line graphic for that particular student and outcome.
Currently, this graphic is hidden behind many many clicks, and it is essential information for anybody interested in measuring progress over time. By contrast, the colored box pertains to a decaying average from which one may not conclude trends of progress, regression or static performance.
This trend line is what Marzano disciples want to see out of their use of Outcomes. I think if it is more readily accessible, that will encourage more adoption of Outcomes generally.