Andrew Thomasson and I disagree. We're doing it, actually, and it's working pretty well so far.
Here's our video explaining the philosophy and basic principles of Mastery:
1. Process of posting to their blog, accessing and using all their Google accounts
2. Making an inference based on evidence
3. Writing an essay that defines who they are through a transformational experience
4. Developing a project that shows mastery of a concept
5. Having a conversation with a group that shows their ability to come to a collaborative definition
6. Reading a text and finding patterns
7. Making meaning of those patterns to determine author's intent
Some of those are processes, and some are about content. This whole first unit is built on the idea of Explore Flip Apply, and all of those skills and processes were developed throughout the unit in that way. As an example:
Explore: Students read a text and find any repeated ideas or patterns. Discuss with group to find commonalities.
Flip: Students watched this video:
We patterned several other texts in that way (some with a video, some with live in-class modelling of the patterns we found), and the final assessment will ask students to pattern a new text and make meaning of it on their own.
Now, we still live in a point-based reality. So somehow, we need to give students points for getting to mastery. The way we decided to make it work is to give students all the points for showing mastery, and none if they didn't. At the end of the unit, the assessment is graded on a rubric, but all other strands are all/nothing. So 20 out of the 55 unit points are graded on a rubric. That means that about 1/3 of the unit points are in the assessment and NOT all/nothing.
If students get all the points for the classwork, the most they can get is an 85% - to get the other 15%, they need to complete the Blank White Page project work for the unit. This is straight-up stolen from Karl Lindgren-Streicher. Thanks, buddy.
The last thing to mention is the Behind Line. That's the date on which work should be completed, but students are not "late" until the unit is over. I don't think we'll take work after the unit is over, but we need to see how it shakes out before deciding for sure. It's all based on the idea that students can work ahead, but not fall behind. Often, we will still do synchronous work in class, so we want students to stay near the same point through this unit. Again, we'll reassess later.
The students are responding positively to this - in fact, they've stopped asking about their grades now, and seem to trust that this is as straight-forward as we keep promising. The true test will come at the end of the unit.