I’m not convinced by the idea of an either-or approach. In other words, BTC practices can’t have any value because they must happen in place of any explicit instruction. In an 85-minute lesson there is plenty of time for students to engage in 15 minutes of inquiry at vertical whiteboards with random groups that foster problem-solving habits and conceptual understanding and still have 60 minutes of direct instruction with mini-whiteboards and notebooks. Doing this well simply requires planning and structure. Just because this hasn’t been rigorously studied in a randomized controlled experiment does not mean that it doesn’t exist.