For example, their activity that explores arcs intercepted by central and inscribed angles. I am very grateful that they make the student investigation handout available as a Word document, so that I can edit the bejeezus out of it. Thank you for that, TI.
The first thing I normally do is insert a problem-to-find after every big conclusion.
They usually ask the student to summarize the finding in words, but "summarizing in words" often turns into "write some BS," at least with my tenth graders. They're just not sure what's expected, so they put some ink on paper and try to make it look good. Asking them to apply the concept to a problem right away really helps.
For example, their culminating question for relating central angles to an intercepted arc looks like this:
and then they move on to inscribed angles. I added this:
The second thing I do usually happens after I've run the activity in class. I notice something that could just be arranged much better to promote student understanding. For example, they put this sequence of questions on two different pages:
And you can forgive a student for being like, what? So I took out question 4 and just added a row to the table:
Another thing that was unclear was how they lead them to notice the relationship between a central angle and an inscribed angle, or the equivalent idea, an inscribed angle and its intercepted arc. Why didn't they put in another nice table, so the numbers are written out and staring them in the face? Were they trying to conserve paper? So I fixed that by adding in another table.
So, conclusion... caveat emptor? There is some fine stuff in there. It just doesn't feel like it was tried out on kids before they published it. Or maybe it's just a case of how you can't really ever just adopt someone else's stuff wholesale without modification, but you have to work through it on your own, modify it, try it out with your kids, and modify it some more.