The Outline of the Survey
As mentioned above, in order to minimize the social desirability bias
when questioning issues of ethical consumption (fair trade in this case),
we used a conjoint measurement of the price consumers were willing to
pay when facing a coffee-buying situation in a supermarket (where most
coffee types are available and which is the usual shopping place of the large
majority of Belgian consumers). In a conjoint analysis, consumers are
asked to indicate their preference (in this case their willingness to pay)
for products with varying characteristics. By simulating real marketplace
situations, conjoint analysis realistically models day-to-day consumer decisions
and has a reasonable ability to predict consumer behavior. Consumers
show their preferences by making trade-offs between different attributes of
a product (Carroll and Green 1995; Green, Krieger, and Wind 2001; Green
and Srinivasan 1978). These trade-offs can be decomposed into part-worth
utilities and importance weights for each product attribute. In this way, the
importance of different attributes or criteria in the consumer’s evaluation of
the product can be studied (Green, Rao, and Desarbo 1978).
Based on an exploratory group discussion with 12 coffee consumers of
varying age, gender, and education, we determined the relevant coffee
attributes and their appropriate levels as follows: