In the first part of the questionnaire, the respondents were asked to
express their willingness to pay for the eight different types of coffee.
A reference product profile was defined (and visually presented) as a coffee
with dessert flavor, a warm package, a blending of Arabica and Robusta
beans, without a fair-trade label, produced by Douwe Egberts, and set at
a price of e1.87 (corresponding to the then-ruling shop price). Respondents
were asked to express their willingness to pay by putting a price over or
under the reference price of e1.87 on each of the eight coffee profiles presented.
By mentioning the fair-trade label in the conjoint task, we could
assume that all respondents were equally informed and that the fairly traded
coffee was perceptible for everybody. The conjoint analysis method
resulted in individual part-worth utilities for each level of each attribute
from which the relative importance of each attribute could be derived.