It offers a unifying definition of HB and presents an integrative framework of how HB relates to but is also distinct from external validity (EV), with HB representing one component of the wider concept of EV. It observes how the variation in operational definitions of HB has prohibited consistent measurement of HB in CE. This paper follows the review of empirical evidence on the existence of hypothetical bias (HB) in choice experiments (CEs) presented in Part I of this study. Our findings have important implications for scaling-up sustainability standards in both emerging and developed markets. Consumers’ preferences for key standard features are associated with individual values, the warm glow of giving, and sustainability concerns but such relationships vary in the two markets. Standard sponsor and origin only matter for consumers in China who favor government-designed, international standards. Moreover, Chinese consumers support highly stringent standards only, whereas British consumers also accept medium-level standards. How do these features affect consumer support across market contexts? By conducting a choice-based conjoint experiment with tea drinkers in China and the UK (N = 1823), we find that consumer support for sustainable tea standards in both countries is primarily driven by food safety concerns, to a lesser extent by concerns of environmental and labor issues. Despite a growing number of studies on consumers' preferences for sustainable products, insufficient attention has been paid to the heterogeneity of existing standard systems, which prioritize different issues (e.g., environment, labor, and health), have different origins and sponsors, imply different costs and stringency. Voluntary standards have become a promising mode of governance to promote sustainable production and consumption in global value chains.

Definition of reliability in research