Validity and Reliability ofOnline Conjoint Analysis

Using conjoint analysis in online surveys is gaining growing interest in market research. Unfortunately there are only few studies that are dealing with the implementing of conjoint analysis in the World Wide Web (WWW). Little is known about specific problems, validity, and reliability using online measures for conjoint analysis. We conducted an online conjoint analysis using a fixed design of thirty paired comparisons. A traditional computerized conjoint analysis was conducted in the same way. Several criteria were used to assess reliability and validity of both data collection methods. The results show that data drawn from an Internet conjoint analysis seem to be somewhat lower in reliability (internal consistency) compared to traditional computerized conjoint analysis. Nevertheless, the reliability seems to be sufficient even in the case of its online form. Regarding predictive validity, both data collection methods lead to comparable results. There is no evidence that the number of thirty paired comparisons might be too high in the case of Internet conjoint analysis. More paired comparisons seem to be favorable taking the moderate internal consistency of responses into account and the additional possibilities of reliability testing. BACKGROUND AND INTRODUCTION After three decades using conjoint analysis there is still a growing interest for choosing this method to analyse preferences and predict choices in marketing research and related fields (Cattin and Wittink, 1982; Wittink and Cattin, 1989; Wittink, Vriens and Burhenne, 1994; Melles and Holling, 1998; Voeth, 1999). The contributions of many researchers have led to a diversification of methods for stimulus-construction, scaling, part-worth estimation, data aggregation and collecting judgments from the subjects. The following paper will focus on techniques for collecting judgments that can be used in conjoint analysis and on an empirical examination of the reliability and validity of the newly introduced method of online conjoint analysis, conducted over the World Wide Web (WWW). Little is known about the quality of data generated by an online conjoint analysis. Is the WWW an appropriate place for collecting complex judgments? Is the quality of this method comparable to that of other collection techniques?