To label or not to label? A meta-regression analysis of consumer willingness to pay for sustainability claims

Background: Sustainability labels (SLs) are increasingly promoted to guide consumer behavior towards more sustainable consumption choices. As a result, research on SLs has increased with numerous studies and reviews highlighting how specific sustainability claims are valued by consumers. Scope and approach: This study presents a comprehensive meta-analysis of willingness to pay (WTP) for SLs displayed on food products, including a wide range of studies focusing on diverse food categories. To conduct the meta-analysis on SLs, Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was used. Key findings and conclusion: The analysis reveals that consumers, on average, are willing to pay a 29 % price premium for products bearing SLs. This mean value masks significant heterogeneity in relation to label and product categories as well as consumer socioeconomic factors. Notably, carbon labels were associated with lower percentage premium WTP, while geographic and animal welfare labels drove higher premiums. From a product perspective, higher percentage premium WTP is observed for SL when used in meat, dairy, alcohol, coffee, and cereals when compared to vegetables. Moreover, consumers in higher-education segments tend to exhibit lower relative WTP, potentially reflecting greater skepticism toward label claims. Percentage WTP premium also decreases with higher product prices, indicating price sensitivity. Studies published after 2017 tend to report higher percentage WTP premium values, possibly linked to increased awareness of sustainability issues. The results empower policymakers, marketers, and stakeholders seeking to design more effective sustainability communication strategies, emphasizing the importance of label type, context, and consumer segmentation.