the last cot step

[nlper-fighting]

Thank you for your great work!
I have a question about the last cot step. include_last_cot is set to False by default. Why did you remove the last CoT step?

[zhenyi4]

Thank you for your question.

We address the motivation in the third paragraph of Section 3.5. For your convenience, I include the relevant passage below:

"For training data, we exclude the final CoT step—the step responsible for generating the final answer—because including this step could allow the teacher’s hidden activations to take a shortcut. Specifically, the model might directly copy the result from the last CoT step to the token responsible for generating the exact answer token, bypassing the reasoning process. This behavior would undermine the quality of the target hidden activations, as they would no longer fully encode the reasoning patterns. The ablation results demonstrating the impact of this exclusion are presented in Table 2."