What's the best way to track consumer preference shifts in sustainable packaging?

The stated vs. actual preference gap is real — we've had good luck combining MaxDiff surveys with behavioral data from shelf tests or eye-tracking to expose it. Conjoint analysis also works well here since people have to make trade-offs (price vs. recyclability vs. aesthetics) rather than just saying 'yes I care about sustainability.' If budget is tight, even a well-designed A/B on your client's e-commerce with real purchase data will tell you more than a survey alone.