Uncovering heterogeneous effects of message framing to promote reusable cup use: A causal forest approach

This study investigated the impact of message framing strategies on promoting reusable cups adoption among South Korean consumers, amid growing global concerns about single-use plastic waste. For this research, we conducted a survey experiment with 1,316 respondents and analyzed their responses to gain framing (discounts for using reusable cups) and loss framing (additional charges for using single-use cups). We also applied causal forest methods to estimate the heterogeneous treatment effects, aiming to provide a deeper understanding of how consumer decisions and behaviors are formed. The results highlighted that loss framing generally outperformed gain framing in encouraging the use of reusable cups. However, significant demographic variations emerged: younger adults (20s–30s) responded better to gain framing, while older adults (40s–60s) were more receptive to a loss framing. The impact of loss framing was particularly powerful among larger families and individuals who prioritize environmental concerns over inconvenience or have high social norms. These findings provide valuable empirical evidence for policymakers and businesses to develop targeted strategies that effectively promote sustainable consumer behavior while maintaining economic efficiency, ultimately contributing to both environmental sustainability and market optimization.