There are many attributes that influence the mode choice in passenger transport. Common stated choice analysis which is often used to model mode choice only allows for a restricted number of attributes to be included in experiments. The Integrated Hierarchical Information Integration approach allows for a larger number of attributes to be analysed. It is applied in this paper in order to study the influence of service quality attributes on mode choice in detail. In this approach similar attributes are grouped into constructs. Separate sub-experiments are designed in which one construct is described by its attributes and the other constructs are included by construct values. Stated choice experiments with train users are conducted in which respondents choose between a regional train, a (hypothetical) regional bus and a car (only available for car users). Besides time and fare/price the two public transport modes are described by attributes and constructs relating to ‘Quality of Connection’, ‘Comfort’, and ‘Information’. Process equality needs to be tested in order to know if the separate sub-experiments may be concatenated into an overall model. A two-stage likelihood ratio test is applied to this end. Process equality is given when analysing only the data of the bi-modal sub-experiments whereas the assumption of process equality is rejected for data of the tri-modal sub-experiments, where differences in error variances between the sub-experiments were found. This empirical finding suggests that it is possible to construct separate sub-experiments while arriving at a single concatenated model.