Hmmmm-- well, their conclusion definitely mirrors what most educators I know have learned empirically in working with students.
Active techniques work better than passive ones. The addition of some stress actually improves learning-- to a point, anyway (the trouble is that this point seems to be highly variable and individual).
On the other hand, "what works" is so dependent upon individual cognitive strengths and weaknesses and learning mode preferences that I find it nearly impossible to believe that generalities are even possible here.
For DH, he remembers what he hears, and to a lesser extent, what he reads. For me, I remember what I read, and to a greater extent, what I WRITE longhand. For DD, she remembers what she talks about with others, and to a lesser extent, what she reads and writes longhand.
What does that mean? Well, I've known my DH for 20+ years, including the 5y that it took to earn terminal degrees. He really can study by highlighting/re-reading. It's effective. For him. He finds practice tests mostly ineffective other than as a desensitizing exercise (managing anxiety).
For me? I learn by rewriting my own notes, or jotting in margins. Practice tests are effective for me.
DD talks. She's about 95% Socratic-- in the old-school definition, I mean. Practice tests are mostly not very effective for her, either.