  Communication success relies heavily on reading participants' reactions. Such
feedback is especially important for mental health counselors, who must
carefully consider the client's progress and adjust their approach accordingly.
However, previous NLP research on counseling has mainly focused on studying
counselors' intervention strategies rather than their clients' reactions to the
intervention. This work aims to fill this gap by developing a theoretically
grounded annotation framework that encompasses counselors' strategies and
client reaction behaviors. The framework has been tested against a large-scale,
high-quality text-based counseling dataset we collected over the past two years
from an online welfare counseling platform. Our study shows how clients react
to counselors' strategies, how such reactions affect the final counseling
outcomes, and how counselors can adjust their strategies in response to these
reactions. We also demonstrate that this study can help counselors
automatically predict their clients' states.
