Measuring the part worth of the mode of transport in a trip package: An extended Bradley-Terry model for paired-comparison conjoint data.

This study measures the travelers' perceived change in utility by accepting one of the modes of transport air, rail, or bus as one component of a packaged city trip. The part-worth values for the trip product elements are expected to depend on a number of traveler characteristics. The predictors hypothesized are city travel experience, general modal preference, socio-economic status, and car ownership. In the survey, the combinations of trip attributes differed between the two subgroups of leisure and business travelers. The leisure travelers rated three levels of mode, length of stay, and price, but only one level of the hotel category. The business travelers were shown four mode alternatives and only two levels for each of the other trip product elements. The conjoint measurements were elaborated by fitting an Extended Bradley-Terry Model. Demonstrating the application of the EBTM is the main purpose of the paper. The EBTM offers several advantages over the more popular versions of conjoint analysis. It correctly treats ties and allows for simultaneous estimation of the trip package ('object') parameters, object covariates (trip attributes), subject covariates (traveler characteristics) and their interactions. For both the business and the leisure travelers, the mode of transport dominated the assessment of a city trip package. For leisure tourists, e.g., switching from train 2nd class to an economy flight boosted the trip package more than twice as much as replacing train for bus. A variation of the package price was much more important for the leisure than for the business travelers. The socio-economic status proved to be an important factor and was particularly influential among the business travelers. In the leisure tourists' sub-sample age was not only important for valuing the mode of transport, but had a preferential impact for all trip components. Finally, the limitations of this demonstration study that discourage extrapolation to city travelers in general are emphasized.