He is a professor in the Department of Economics at the University of Colorado in Boulder.His teaching and research interests include environmental economics, microeconomic theory, and econometrics. He has a particular interest in nonmarket valuation; that is, valuing commodities that are not directly bought and sold in the market place. This work spans demand theory and the estimation of consumer's surplus. Topics include the random components in utility and demand functions, the importance of individual and commodity characteristics in explaining choice, the importance of time costs, and corner solutions. His applied work includes estimating the consumer's surplus different individuals associate with changes in the characteristics and/or existence of ski areas, fishing sites, mountain bike trails, open space and historical monuments.