Which frame fits? Policy learning with framing for climate change policy attitudes

How should climate policy be framed to maximize public support? We evaluate the effects of five distinct message frames—scientific, religious, moral, and two economic (efficiency and equity)—on support for climate change policy using a randomized experiment with over 2300 U.S. respondents. Moving beyond pairwise frame comparisons, we adopt a policy learning approach that identifies the most effective frame using cross-validated sample splitting, thereby avoiding selective inference. We find that the economic efficiency frame consistently yields the largest gains in policy support, outperforming both the control condition and all alternative frames, on average. While the effects of covariate conditional frame assignment were modest and not significantly different from assigning the best overall frame, we find consistent positive effects of the efficiency frame across partisan subgroups. Our findings offer methodological and substantive contributions: we highlight how policy-learning methods can be applied in experimental framing studies, and we offer specific evidence on the relative efficacy of alternative framing messages on support for several climate policies.