MODELING MOVEMENTS IN INDIVIDUAL CONSUMPTION: A TIME‐SERIES ANALYSIS OF GROUPED DATA

We characterize the time‐series properties of group‐level consumption, income, and interest rates using microdata. We relate the coefficients of moving average representations to structural parameters of theoretical models of consumption behavior. Using long time series of cross sections to construct synthetic panel data for the United Kingdom, we find that for high‐educated individuals the Euler equation restrictions are not rejected, the elasticity of intertemporal substitution is higher than one, and there is evidence of “excess smoothness” of consumption. Low‐educated individuals, conversely, exhibit excess sensitivity of consumption to past income, and the elasticity of intertemporal substitution is not statistically different from zero.     

Augmenting travel cost models with contingent behavior data

This paper proposes contingent behavior survey questions as a valuable supplement to observed data in travel cost models of non-market demand for recreational resources. A set of observed and contingent behavior results for each survey respondent allows the researcher to control for individual heterogeneity by taking advantage of panel data methods when exploring the nature of respondent demands. The contingent scenarios also provide opportunities to (a) test for differences between observed and contingent preferences and/or (b) assess likely demands under conditionsbeyond the domain of observed variation in costs or resource attributes. Most importantly, contingent scenarios allow the researcher to imposeexogenously varying travel costs. Exogenous imposition of travel costs together with panel methods reduces the omitted variables bias that plagues observed-data travel cost models of recreational demand. Using a convenience sample of data for illustrative purposes, we show how to estimate the demand for recreational angling by combining observed and contingent behavior data. We begin with simple naive pooled Poisson models and progress to more theoretically appropriate fixed effects panel Poisson specifications.The authors are at the University of Nevada and UCLA, respectively. We gratefully acknowledge the comments of both Scott Shonkwiler and participants in the W133 meetings in Santa Fe, New Mexico and for research material provided by Wayne Gray. The data were provided by Rang Narayanan. Research assistance was provided by Jerry McGraw and Natalie Tucker. Research partially supported by the Nevada Experiment Station. Any errors or omissions remain the authors' responsibility.     

Nonlinear models with panel data

Panel data play an important role in empirical economics. With panel data one can answer questions about microeconomic dynamic behavior that could not be answered with cross sectional data. Panel data techniques are also useful for analyzing cross sectional data with grouping. This paper discusses some issues related to specification and estimation of nonlinear models using panel data.JEL Classification: C230The research behind this paper was supported by the National Science Foundation, the Gregory C. Chow Econometric Research Program at Princeton University, and Danish National Research Foundation (through CAM at the University of Copenhagen). The author thanks Ekaterini Kyriazidou, Hong Li, Marina Sallustro, and the editors for helpful suggestions.     

APPLICATION OF PANEL DATA MODELS IN BENCHMARKING ANALYSIS OF THE ELECTRICITY DISTRIBUTION SECTOR*

ABSTRACT ** : This paper explores the application of several panel data models in measuring productive efficiency of the electricity distribution sector. Stochastic Frontier Analysis has been used to estimate the cost‐efficiency of 59 distribution utilities operating over a nine‐year period in Switzerland. The estimated coefficients and inefficiency scores are compared across three different panel data models. The results indicate that individual efficiency estimates are sensitive to the econometric specification of unobserved firm‐specific heterogeneity. This paper shows that alternative panel models such as the ‘true’ random effects model proposed by Greene (2005) could be used to explore the possible impacts of unobserved firm‐specific factors on efficiency estimates. When these factors are specified as a separate stochastic term, the efficiency estimates are substantially higher suggesting that conventional models could confound efficiency differences with other unobserved variations among companies. On the other hand, refined specification of unobserved heterogeneity might lead to an underestimation of inefficiencies by mistaking potential persistent inefficiencies as external factors. Given that specification of inefficiency and heterogeneity relies on non‐testable assumptions, there is no conclusive evidence in favour of one or the other specification. However, this paper argues that alternative panel data models along with conventional estimators can be used to obtain approximate lower and upper bounds for companies' efficiency scores.     

Competition and Costs: Evidence from Competitive Tendering in the Scottish National Health Service

This paper estimates the impact of competitive tendering on cleaning costs in Scottish National Health Service hospitals. Unlike previous studies, which have relied on cross‐sectional data, a five‐year balanced panel of 176 hospitals is used to estimate a series of fixed effects regression models. These panel estimates suggest that previous studies have likely over‐estimated the cost‐savings associated with competitive tendering. The findings also suggest that the lower costs associated with competitive tendering have more to do with auction theory than with any intrinsic efficiency of the private sector.     

Equivalence Scales in an Intertemporal Setting with an Application to the Former West Germany

Equivalence scales provide answers to questions like how much a household with two children needs to spend compared to a couple to attain the same welfare level. These are important questions for child allowances, social benefits and to assess the cost of children over the life-cycle for example. We discuss equivalence scales in an intertemporal setting with uncertainty. To estimate equivalence scales we use a panel from German households (GSOEP) containing subjective data on satisfaction with life and satisfaction with income to represent the welfare level. Because satisfaction is measured on a discrete scale we use limited dependent variable models for panel data in estimation. Using satisfaction with life data we find that larger households do not need any additional income to be as satisfied as a couple. Using satisfaction with income, however, yields equivalence scales that increase with household size.     

The time–covariance function: Properties and application

This note establishes the relationship between the time interval over which changes in two random variables are measured and the covariances between these changes for various intervals. It then shows that the properties of this relationship can be used to detect the presence of intertemporal cross serial correlations between time series data.     

Heroin Consumption,Prices and Addiction: Evidence from Self‐reported Panel Data*

Estimation models of drug demand should encompass the aspect of addiction. Here, we consider two static panel data regression models and two cross‐section models with lags or leads in drug consumption as additional regressors. Heroin injectors attending a needle exchange service in Oslo were interviewed twice, with a one‐year interval. Despite our relatively small sample, we obtain statistically significant price and income responses for nearly all of the models and specifications applied. The sample is split by dealing status, with dealers obtaining price elasticities in the range of [?0.15, ?1.51] and non‐dealers [?0.71, ?1.69]. Somewhat surprisingly, the estimates of the variance of the latent individual‐specific variable are rather low in the panel data models, although higher for non‐dealers than for dealers.     

Regulation and efficiency in transition: the case of Romanian banks

Using disaggregated panel data for the period 1996–2002, this paper estimates the cost efficiency of Romanian banks and relates it to regulation implemented by the National Bank of Romania. We estimate efficiency using a model that combines the frameworks of both stochastic frontier analysis and shadow cost functions. Our results indicate that, for all types of banks, the cost of technical inefficiency decreases in the years following tightening of regulation. A significant part of this decrease can be attributed to the policy change. Overall, the short-run increase in cost due to additional regulation exceeds the benefits from reduced technical inefficiency. However, our model does not account for other benefits, besides changes in X-inefficiency, such as stability of the banking system, which may be significant.      

The impact of technology and trade upon the returns to education and occupation

This paper considers how technological change and globalization has influenced the return to education and occupation in Great Britain over the period 1973 to 1994. A number of papers in the literature have documented increasing demand for individuals who possess higher skill endowments than their peers. Both education and occupation can be interpreted as an individual's observable skills and how technology and trade have actually influenced returns to different educational and occupational levels is something that has not been investigated in Great Britain. For the empirical analysis estimates are based upon pooled cross sections over time and also pseudo panel techniques to control for unobservable heterogeneity.     

Endogenously chosen travel costs and the travel cost model: an application to mountain biking at Moab,Utah

The travel cost model is frequently used to estimate net willingness to pay for recreation at remote sites by using the visitor's travel costs as a proxy for the price of recreation. However, some concern has been raised over the validity of using the visitor's stated travel costs as a proxy for price. This paper addresses some of these concerns, by examining the possible over-estimation of consumer surplus due to endogenously chosen travel costs. This paper extends past theoretical work for the linear model by developing a correction for endogenously chosen travel costs in more commonly used nonlinear models such as the Poisson or count data model. Also provided is the first empirical test of the presence of endogeneity and an estimate of the magnitude of the error from ignoring endogeneity in travel costs. After applying this test and the correction to data that was gathered for mountain biking at Moab, Utah the estimate of consumer surplus falls from US $153 to US $135, which is a 12% reduction.     

Estimating the private benefits of vaccination against cholera in Beira, Mozambique: A travel cost approach

This paper reports the results of the first study that estimates households' private demand for cholera vaccines using the travel cost method. We take advantage of an unusual natural experiment. In January 2004, more than 41,000 residents from various locations in Beira, Mozambique received two doses of oral cholera vaccine free of charge during the first vaccination trial to test its effectiveness in an endemic cholera zone of Africa. About 30,000 people participated from outside the target zone, resulting in long queues and an average waiting time of about 85 min per dose.We estimated travel cost models of the revealed demand for cholera vaccines among households informed of the trial using information collected in in-person interviews conducted during the summer of 2005. To explore households' participation in the trial, we used standard and zero-inflated household count models for all household members and dichotomous choice models for the head of the household. Our analysis shows that the quantity of vaccines obtained by households and the likelihood of participation decreased as travel cost—in time and transport expenses—rose. Our best estimates of per capita willingness to pay for the two required doses of cholera vaccine are about 0.85 USD. These estimates are sensitive to the assumed value of time spent acquiring vaccines.     

A differentiated tolls system – an effective transport policy tool for Slovenia?

We provide an econometric model of passenger and freight transportation demand based on panel data for 10 sections of toll roads in Slovenia. Transportation demand on Slovenian motorways is price inelastic. The price elasticity of transportation demand statistically varies among different parts of the toll sections, so it would seem sensible to introduce a differentiated toll system that would allow the simultaneous achievement of multiple objectives, such as increasing the internalization of the external costs of transport, increasing transportation demand management on the basis of price and increasing cost recovery for the maintenance and development of toll roads in Slovenia. Transportation demand is even more responsive to changes in fuel price than changes in tolls, so transportation policy can manage transportation demand using differences in fuel prices. Based on estimates of demand models differentiated according to several geographical groups of road sections, we also find that growth in the price elasticity of transportation demand in Slovenia can be achieved through the expansion of the transport supply by increasing the competitiveness of rail transport and alternative transportation routes.     

INTERTEMPORAL COMPLEMENTARITY AND OPTIMALITY: A STUDY OF A TWO‐DIMENSIONAL DYNAMICAL SYSTEM*

We study the underlying structure of the two‐dimensional dynamical system generated by a class of dynamic optimization models that allow for intertemporal complementarity between adjacent periods, but preserve the time‐additively separable framework of Ramsey models. Specifically, we identify conditions under which the results of the traditional Ramsey‐type theory are preserved even when the intertemporal independence assumption is relaxed. Local analysis of this theme has been presented by Samuelson (Western Economic Journal 9 (1971), 21–26). We establish global convergence results and relate them to the local analysis, by using the mathematical theory of two‐dimensional dynamical systems. We also relate the local stability property of the stationary optimal stock to the differentiability of the optimal policy function near the stationary optimal stock, by using the Stable Manifold Theorem.     

PANEL DATA HEDONICS: ROSEN'S FIRST STAGE AS A “SUFFICIENT STATISTIC”

Traditional cross-sectional estimates of hedonic price functions can recover marginal willingness to pay for characteristics, but face endogeneity problems for estimating nonmarginal welfare measures. This article shows that when panel data on household demands are available, one can construct a second-order approximation to nonmarginal welfare measures using only the first-stage marginal prices. With repeated cross sections of product prices, the measure can be set identified or, under a single-crossing restriction, point identified. Bounds also can be constructed when there are mobility costs. Finally, a variant remains valid when individual preferences shift over time.     

环境库兹涅茨曲线假说及其在中国的检验

经济与环境协调发展是我国经济发展中的重大课题。本文从环境库兹涅茨曲线假说出发,利用中国各个省市区1989～2004年数据建立面板数据模型,运用固定效应模型和随机效应模型对其进行估计,以此剖析我国经济增长与环境污染水平的演变规律。结果表明,环境库兹涅茨曲线假说在我国并不成立。因此,我国不能盲目重复发达国家"先污染,后治理"的传统模式,而应该走环境与经济持续协调发展的道路。     

Exploring policy options in joint intertemporal-spatial trade models using an incomplete markets approach

In this paper we discuss the desirability of service trade liberlization in the presence of incompleteness of markets where there is both inter-spatial and intertemporal trade between countries. We use numerical simulation methods for insights and relate our discussion to the General Agreement on Trade in Services (GATS) in the WTO. We interpret the absence of intertemporal trade as an absence of intermediation services provided by both domestic and foreign service providers. For simplicity, we consider extreme cases where intertemporal intermediation services can only be provided by domestic providers, so that when intertemporal trade in services is not allowed, markets are not complete. To our knowledge, this type of models is not used in the trade literature as general comparative statics results are unavailable. We first consider the liberalization of trade in financial services in an inter-spatial and intertemporal model of two countries, and we show how services liberalization can be welfare worsening in the presence of a tariff on spatial trade in goods. We show that this can hold in an artificial world with no domestic financial services provider. We compare financial service trade autarky in which there is no intermediation to financial service trade liberalization which involves costless intertemporal intermediation provided by foreign service providers. We also consider a more complex (and realistic) world where costly intermediation services can be provided by both domestic and foreign providers. This paper draws in part on material of an earlier paper, “Financial Services Trade Liberalization in A Joint Spatial Intertemporal Multi-Country Model” by Huang et al. (2004). We acknowledge the financial support from The Centre for Intentional Governance Innovation (CIGI), Waterloo, Canada and from National Social Science Foundation of China (SSFC Grant 07AJL002), National Natural Science Foundation of China (NSFC Grant 70825003) and “Humanities and Social Science” Major Project, Chinese Ministry of Education (Grant Number 07JJD790145).     

The role of boundary solutions in principal-agent problems of the Holmström-Milgrom type

The paper extends the Holmström-Milgrom [B. Holmström, P. Milgrom, Aggregation and linearity in the provision of intertemporal incentives, Econometrica 55 (1987) 303-328] analysis of intertemporal incentive provision to allow for the implementation of actions on the boundary of the feasible set. Boundary actions provide the principal with some freedom in choosing incentive schemes. This can be used to reduce premia. The paper characterizes optimal incentive schemes for the continuous-time Brownian-motion model and its discrete-time approximations. Linearity of incentive schemes in “accounts” is confirmed. However, for models with effort costs depending only on mean returns, the availability of boundary actions destroys the linearity of optimal incentive schemes in profits.     

A Model of Endogenous Nontradability and its Implications for the Current Account*

This paper studies how nontraded goods limit the ability of a country to finance current account deficits. It uses an intertemporal model of the current account for a small open economy where goods are endogenously nontraded due to explicit trade costs. The economy has an endowment of two goods with differing trade costs, either of which can be traded or nontraded in equilibrium. The model implies that current account deficits impose a cost, in the form of raising the effective interest rate in the country. The findings differ from some recent studies: first, in that the interest rate rises even for countries with modest current account deficits; secondly, the interest rate cost eventually reaches an upper bound as current account deficits grow, and progressively more nontraded goods become traded to service the debt. Panel regression analysis of interest rate and current account data is consistent with our conclusions.     

Credit Constraints,Technology Choice and Exports: A Firm‐level Study for Latin American Countries

In this paper, constraints on technology choice and credit access are introduced into a firm‐level trade model in a dynamic setting in order to explain factors that limit benefits to a firm from trade liberalization. Theoretical analysis shows that firms face credit constraints depending on their initial productivity and the cost of credit. As a result, credit‐constrained firms may not be able to cross the minimum productivity threshold needed to enter and compete in a foreign market. Empirical analysis using firm‐level panel data for six Latin American countries confirms that financial constraints negatively influence firms' export and investment decisions.