The effect of attribute-alternative matrix displays on preferences and processing strategies

When analyzing discrete choice data we assume that respondents compare alternatives and make a utility maximizing choice. The majority of DCEs use a matrix display with one row per attribute and one column per alternative. A comparison by alternatives implies that respondents process the choice task column-by-column. However, evidence from psychology and judgment and decision making research suggest that learned reading patterns dominate and as such the standard matrix display might induce processing by attributes rather than alternatives. We test this using a split sample survey conducted in France where respondents were randomly allocated into a standard or transposed matrix display group. Our results show that there is no difference in relative scale between the two groups, but that elicited preferences differ. Importantly, ASCs are insignificant in the transposed condition. We find no difference in propensity to use simplifying strategies, but respondents in the standard display condition are more likely to choose according to a random regret minimization (RRM) model rather than random utility model (RUM). We discuss the implications of our findings for future discrete choice experiments.