Errors in variables in multinomial choice modeling: A simulation study applied to a multinomial logit model of travel mode choice

Modeling travel demand is a vital part of transportation planning and management. Level of service (LOS) attributes representing the performance of transportation system and characteristics of travelers including their households are major factors determining the travel demand. Information on actual choice and characteristics of travelers is obtained from a travel survey at an individual level. Since accurate measurement of LOS attributes such as travel time and cost components for different travel modes at an individual level is critical, they are normally obtained from network models. The network-based LOS attributes introduce measurement errors to individual trips thereby causing errors in variables problem in a disaggregate model of travel demand. This paper investigates the possible structure and magnitude of biases introduced to the coefficients of a multinomial logit model of travel mode choice due to random measurement errors in two variables, namely, access/egress time for public transport and walking and cycling distance to work. A model was set up that satisfies the standard assumptions of a multinomial logit model. This model was estimated on a data set from a travel survey on the assumption of correctly measured variables. Subsequently random measurement errors were introduced and the mean values of the parameters from 200 estimations were presented and compared with the original estimates. The key finding in this paper is that errors in variables result in biased parameter estimates of a multinomial logit model and consequently leading to poor policy decisions if the models having biased parameters are applied in policy and planning purposes. In addition, the paper discusses some potential remedial measures and identifies research topics that deserve a detailed investigation to overcome the problem. The paper therefore significantly contributes to bridge the gap between theory and practice in transport.     

Congestion and Optimal Immigration Policy

This paper presents a model to explain the stylized fact that many countries have a low ratio of migrants in their population while some countries have a high ratio of migrants. Immigration improves the income of the domestic residents, but migrants also increase the congestion of public services. If migrants are unskilled and therefore pay low taxes, and the government does not limit access to these services, then the welfare of the domestic residents decreases with the number of migrants. Visa auctions can lower the cost of immigration control and substitute legal migrants for illegal migrants. If the government decides to limit the access of migrants to public services, immigration control becomes unnecessary and the optimal number of migrants can be very large.     

Advertising,the matchmaker

We empirically study the informational role of advertising in matching consumers with products when consumers are uncertain about both observable and unobserved program attributes. Our focus is on the network television industry, in which the products are television shows. We estimate a model that allows us to distinguish between the direct effect of advertising on utility and its effect through the information set. A notable behavioral implication is that exposure to informational advertising can decrease the consumer’s tendency to purchase the promoted product. The structural estimates imply that an exposure to a single advertisement decreases the consumer’s probability of not choosing her best alternative by approximately 10%. Our results are relevant for industries characterized by product proliferation and horizontal differentiation.     

Trade policies,macroeconomic adjustment,and manufactured exports: The Latin American experience

Conclusions Changes in trade policy, especially in quantitative import restrictions, have played an important role in the macroeconomic adjustment in all six countries. For long periods, trade policy tightenings and occasional liberalizations were the main instruments of balance-of-payments policy. Most tightenings were preceded by a deterioration in the current account. In several cases tight import restrictions had adverse effects on output and, hence, on investment and growth. Since changes in trade policies, referred to here as episodes, were usually part of a policy package, it is difficult to isolate the effects of the episodes themselves. Sometimes they have been followed by current account improvements and other times by deteriorations.     

Public Information Quality with Monopolistic Sellers

We show that in markets with asymmetric information, even if there is full agreement on the choice of optimal information quality, entrusting the choice of (unverifiable) public information quality to traders who benefit from such information leads to inefficiencies. However, delegation of information quality choice to an independent agent who is precluded from sharing in trading profits results in efficient implementation. This result provides a game-theoretic rationale for current institutional arrangements where a private organization that is independent of market traders, the Financial Accounting Standards Board, determines the standards for public disclosures.Journal of Economic LiteratureClassification Numbers: D41, D42, D82.     

LONG-RUN RELATIONS IN EXCHANGE MARKETS: A TEST OF COVERED INTEREST PARITY

We examine long-run relations implied by covered interest parity (CIP) in possibly cointegrated and nonstationary data series. Empirical evidence suggests that, ignoring market imperfections, CIP failed over January 6, 1984, through December 6, 1991, using weekly data from four major currencies relative to the U.S. dollar. The multivariate maximum likelihood vector autoregressive (VAR) methodology does not require data differencing and hence retains valuable information lost in previous research examining international market flows. Rejections are robust to both subperiod analysis and alternative interest rate series. Although test rejections are highly statistically significant, attainable economic profits appear small. Practitioners will find economic profits inconsequential relative to reasonable bounds on market frictions such as transaction costs. Nonetheless, the use of CIP to determine forward rates identically from interest rates and spot rates in academic studies is called into question.     

Ranking agencies under moral hazard

Summary. We provide rankings across uncertain outputs generated by agents functioning within the Principal-Agent paradigm. For agents who are identical except for their productivity, a necessary (but not sufficient) condition for an agent to be preferred is that her output dominates that of lower agents in the sense of First Degree Stochastic Dominance (FDSD) at every level of effort. Sufficient conditions are based on Blackwells ranking of information systems and involves a characterization of FDSD using stochastic matrices. Our conditions for ranking outputs extends earlier results concerning the value of information within the agency framework. We also show how our techniques can be adapted to rank agents even if the first-order approach for determining optimal contracts fails to hold.Received: April 2, 1996; revised version: October 30, 1996This revised version was published online in February 2005 with corrections to the cover date.     

Uncertain litigation and liability insurance

Legal penalties and liability insurance seem to have counteracting effects on the incentives of a potential injurer to take due care. However, if legal penalties are set efficiently and implemented perfectly, unrestricted access to insurance can be optimal. In contract, if the standards of guilt assessment are uncertain, the size of the legal penalties may act as a spur to litigation. Therefore, the penalties required to maintain incentives when access to insurance is unlimited may provoke too much litigation, and as a consequence, the costs of ensuring due care may decline when insurance is restricted by mandate.     

Equilibrium Unemployment Rate and Customs Union

This paper utilizes the macroeconomics concept of the equilibrium rate of unemployment for theorems on free trade and the formation of customs union. The notion of an equilibrium rate of unemployment appears in the literature on labour, macroeconomics, business cycles and trade theory. Such an equilibrium rate can be derived in a number of ways, for example, by introducing labor–leisure choice in the utility functions of the workers; a labor turnover model and/or by introducing shirking. We extend the two sector-two factor Heckscher–Ohlin–Samuelson model for a small open economy by relaxing the assumption of inelastic labor supply. Specifically, we consider the classical labor supply function obtained from the representative consumer's utility maximisation problem. This consideration allows for the existence of unemployment and we analyse the effects trade policies have on the equilibrium unemployment rate. Given the movement towards free trade (either via the implementation of GATT and/or formation of customs union) it is important to examine its implications for the equilibrium rate of unemployment.