In conjoint analysis, respondents use holdout data to make choices from sets of alternative objects described on the same attributes (Wittink and Bergesteum 2001). Ideally, holdout choice sets have characteristics that resemble actual choices respondents will face in the future.

• Wittink, D. R. & T. Bergestuen (2001), “Forecasting with conjoint analysis,” in J. S. Armstrong (ed.), Principles of Forecasting. Norwell, MA: Kluwer Academic Press.