A Multivariate Ordered Response Model System for Adults’ Weekday Activity Episode Generation by Activity Purpose and Social Context Nazneen Ferdous The University of Texas at Austin Dept of Civil, Architectural & Environmental Engineering 1 University Station C1761, Austin TX 78712-0278 Phone: 512-471-4535, Fax: 512-475-8744 E-mail:
[email protected] Naveen Eluru The University of Texas at Austin Dept of Civil, Architectural & Environmental Engineering 1 University Station C1761, Austin TX 78712-0278 Phone: 512-471-4535, Fax: 512-475-8744 E-mail:
[email protected] Chandra R. Bhat* The University of Texas at Austin Dept of Civil, Architectural & Environmental Engineering 1 University Station C1761, Austin TX 78712-0278 Phone: 512-471-4535, Fax: 512-475-8744 E-mail:
[email protected] Italo Meloni The University of Cagliari, Department of Territorial Engineering Piazza d'Armi, 09123 Cagliari, Italy Phone: 39 70 675-5268, Fax: 39 70 675-5261 E-mail:
[email protected] *corresponding author The research in this paper was completed when the corresponding author was a Visiting Professor at the Department of Territorial Engineering, University of Cagliari. Original submission - August 2009; Revised submission - January 2010 ABSTRACT This paper proposes a multivariate ordered response system framework to model the interactions in non-work activity episode decisions across household and non-household members at the level of activity generation. Such interactions in activity decisions across household and non- household members are important to consider for accurate activity-travel pattern modeling and policy evaluation. The econometric challenge in estimating a multivariate ordered-response system with a large number of categories is that traditional classical and Bayesian simulation techniques become saddled with convergence problems and imprecision in estimates, and they are also extremely cumbersome if not impractical to implement.