This paper tests if second-price Vickrey auction (SPVA) and discrete choice experiment (DCE) are isomorphic, and whether lack of isomorphism is due to value elicitation, value-formation or both. We conduct an artefactual field experiment that combines induced-value (IV) and home-grown (HG) procedures using SPVA and DCE. Induced-value preferences are elicited for tokens and HG preferences for multi-attribute lasagnes. Attributes are healthiness and environmental sustainability. Our results suggest that HG preferences differ across elicitation methods. This discrepancy is due to value-elicitation and value-formation. DCE is the most demand revealing approach and provides the highest premiums for healthy and environmentally sustainable lasagnes.