An analysis of multiple interepisode durations using a unifying multivariate hazard model

This paper jointly examines the length between successive participations in several activity purposes using a 1999 multi-week travel survey conducted in the German cities of Halle and Karlsruhe. A multivariate hazard model that accommodates a flexible duration dynamics structure, recognizes the effects of covariates, incorporates the variation in interepisode duration due to unobserved individual-specific factors and variation in interepisode duration within spells of the same individual, and considers the joint nature of participation in the various activities is proposed and applied. The variables considered in the analysis include demographics, access to the internet, location characteristics, and day of week variables. The results indicate a very distinct weekly rhythm in individuals' participation in social, recreation, and personal business activities. While there is a similar rhythm even for participation in shopping activities, it is not as pronounced as for the non-shopping activity purposes. Also, individuals and spouse attributes, household characteristics, residential location and trip-making variables, and day of week effects have a strong influence on interepisode durations.