Conjoint Analysis on Objects with Environmentally Correlated Attributes: The Questionable Importance of Representative Design

When studying objects with environmentally correlated attributes, the use of orthogonal arrays in conjoint analysis can produce some highly unrealistic stimuli that might threaten a study's ecological validity. The effect of such departures from realism induced by environmental correlations is examined. A series of three experiments compares a stimulus set that has non-zero, but lower than environmental, correlations to one using an orthogonal array in terms of both perceived realism and predictive power. The results indicate that environmentally correlated attributes may pose fewer problems in practice than in theory.