Best way to test sustainable packaging claims with shoppers?

Conjoint is a solid call here — discrete choice with 'recyclable' vs 'compostable' as an attribute alongside price and brand will give you clean trade-off data. We ran something similar using Qualtrics conjoint with ~300 respondents and the lift difference between the two claims was actually pretty surprising (compostable won, but only for certain categories). If budget is tight, a simple monadic split test with purchase intent scales can also get you directional answers fast.