nep-dcm New Economics Papers
on Discrete Choice Models
Issue of 2007‒08‒27
two papers chosen by
Philip Yu
Hong Kong University

  1. Constructing Krinsky and Robb Confidence Interval for Mean and Median WTP Using STATA By P. Wilner Jeanty
  2. Market Potential and Income Inequality By Nilsson, Desirée

  1. By: P. Wilner Jeanty (The Ohio State University)
    Abstract: The ultimate goal of most non-market valuation studies is to obtain welfare measures i.e. mean and/or median willingness to pay (WTP) and confidence intervals. While the delta (nlcom) and bootstrap (bs) methods can be used for constructing such confidence intervals in Stata, they are not recommended because WTP measures are non-linear functions of random parameters (Creel and Loomis, 1991). The best and widely used approach, which is not available in Stata, consists in simulating the confidence intervals using the Krinsky and Robb procedure (Haab and McConnell, 2002). Hole (2007) has recently introduced a useful command, wtp, which implements the Krinsky and Robb procedure in Stata, but does not feature mean and median WTP estimates and their confidence intervals. I present a Stata command, wtpcikr, which computes mean and median WTP, confidence intervals using the Krinsky and Robb procedure, achieved significance level (ASL) for testing the null hypothesis that WTP equals zero, and a relative efficiency measure (Loomis and Ekstrand, 1998). The command supports both linear and exponential contingent valuation models estimated with or without covariates using the Stata commands probit, logit, biprobit, and xtprobit. I will illustrate the use of wtpcikr by replicating empirical results in Haab and McConnell (2002).
    Date: 2007–08–15
  2. By: Nilsson, Desirée (JIBS and CESIS)
    Abstract: This study assumes that non-homothetic preferences determine the flow of international trade. Empirical studies of international trade have commonly only considered demand from a representative consumer. This would not provide a complete picture of the aggregate market demand. Because of the prevalence of non-homothetic preferences in demand, firms that contemplate exports should consider the distribution of income within a country as an attribute of the corresponding market. This study evaluates the effect that income inequality may exert on a firm’s probability of selecting a particular export market. The theoretical framework is supported by discrete choice theory, and the empirical analysis uses export statistics for the OECD countries. The results indicate that uneven income distribution is perceived as an attractive feature of destinations for exports.
    Keywords: market potential; income inequality; discrete choice theory
    JEL: D31 F10
    Date: 2007–08–08

This nep-dcm issue is ©2007 by Philip Yu. It is provided as is without any express or implied warranty. It may be freely redistributed in whole or in part for any purpose. If distributed in part, please include this notice.
General information on the NEP project can be found at For comments please write to the director of NEP, Marco Novarese at <>. Put “NEP” in the subject, otherwise your mail may be rejected.
NEP’s infrastructure is sponsored by the School of Economics and Finance of Massey University in New Zealand.