SEMI-PARAMETRIC ESTIMATION OF HURDLE REGRESSION MODELS WITH AN APPLICATION TO MEDICAID UTILIZATION

This paper develops a semi-parametric estimation method for hurdle (two-part) count regression models. The approach in each stage is based on Laguerre series expansion for the unknown density of the unobserved heterogeneity. The semi-parametric hurdle model nests Poisson and negative binomial hurdle models, which have been used in recent applied literature. The empirical part of the paper evaluates the impact of managed care programmes for Medicaid eligibles on utilization of health-care services using a key utilization variable, the number of doctor and health centre visits. Health status measures and age seem to be more important in determining health-care utilization than other socio-economic and enrollment variables. The semi-parametric approach is particularly useful for the analysis of overdispersed individual level data characterized by a large proportion of non-users, and highly skewed distribution of counts for users. © 1997 John Wiley & Sons, Ltd.     

ESTIMATION OF TREATMENT EFFECTS WITHOUT AN EXCLUSION RESTRICTION: WITH AN APPLICATION TO THE ANALYSIS OF THE SCHOOL BREAKFAST PROGRAM

The increase in childhood obesity has garnered the attention of many in policymaking circles. Consequently, school nutrition programs such as the School Breakfast Program (SBP) have come under scrutiny. The identification of the causal effects of such programs, however, is difficult owing to non‐random selection into the program and the lack of exclusion restrictions. Here, we propose two new estimators aimed at addressing this situation. We compare our new estimators to existing approaches using simulated data. We show that while correlations might suggest that SBP causes childhood obesity, SBP is likely to reduce childhood obesity once selection is addressed. Copyright © 2012 John Wiley & Sons, Ltd.     

A DOUBLE LENGTH REGRESSION COMPUTATION METHOD FOR THE 2SGLS ESTIMATOR OF RATIONAL EXPECTATIONS MODELS

ABSTRACT This paper extends a matrix inverse result of Higgins and presents a new unified double length regression method to calculate the two-step generalised least squares estimators of two types of rational expectations model with current anticipated and unanticipated components. The estimator can be applied directly in most of the standard econometric computer packages such as PC-Give and Microfit.     

ENDOGENEITY IN COUNT DATA MODELS: AN APPLICATION TO DEMAND FOR HEALTH CARE

The generalized method of moments (GMM) estimation technique is discussed for count data models with endogenous regressors. Count data models can be specified with additive or multiplicative errors. It is shown that, in general, a set of instruments is not orthogonal to both error types. Simultaneous equations with a dependent count variable often do not have a reduced form which is a simple function of the instruments. However, a simultaneous model with a count and a binary variable can only be logically consistent when the system is triangular. The GMM estimator is used in the estimation of a model explaining the number of visits to doctors, with as a possible endogenous regressor a self-reported binary health index. Further, a model is estimated, in stages, that includes latent health instead of the binary health index. © 1997 John Wiley & Sons, Ltd.     

INTER-REGIONAL TRADE FLOW ESTIMATION THROUGH NON-SURVEY MODELS: AN EMPIRICAL ASSESSMENT

Inter-regional trade estimation has been pointed out as a crucial problem when constructing a multiregional input–output system. Knowledge of inter-regional trade flows, at least of the pooled volume of exports and imports by commodity, is critical in accounting for important spillover and feedback effects deriving from inter-regional linkages. However, in most countries, there are no completely reliable survey-based statistics on inter-regional trade. Thus, this paper intends to evaluate the reasonability of using indirect inter-regional trade estimates, comparing different estimating methods and assessing the sensitivity of the model results. Based on our empirical comparisons we conclude that input–output models are not greatly affected by the insertion of different trade values. Thus, our results support the use of indirect estimates for inter-regional trade, whenever survey-based data are unavailable.     

MATCHING MODELS UNDER SCRUTINY: AN APPRAISAL OF THE SHIMER PUZZLE

Abstract Two papers have recently questioned the quantitative consistency of the search and matching model. Shimer has argued that a textbook matching model is unable to explain the cyclical variation of unemployment and vacancies in the US economy. Costain and Reiter have found the existence of a trade‐off in the model's performance: any attempt to change the calibrated values to improve the model's ability to predict the business cycle jeopardizes its predictions of the impact of unemployment benefits on unemployment. In surveying the literature originating in these findings, I distinguish three different avenues that have been followed to correct the model: change in wage formation, change in the calibration and changes in the model specification. The last approach seems to achieve the best results both from a business cycle and from a microeconomic viewpoint.     

EXTENSIONS TO THE MULTIPLIER DECOMPOSITION APPROACH IN A SAM FRAMEWORK: AN APPLICATION TO VIETNAM

The aim of this paper is to provide an extension of a technique recently introduced by Pyatt and Round (2006) to decompose each element of the ‘global multiplier matrix’ in ‘microscopic detail’ in order to capture the linkages between each household groups’ income and the exogenously injected income of other accounts. The methodology we propose allows dividing the impact of exogenous injections into four different effects: direct-direct effect (D-D); direct-indirect effect (D-I); indirect-direct effect (I-D) and indirect-indirect effect (I-I). Results using the 2000 Vietnamese SAM show that the highest direct effects on the income of household groups are related to exogenous injections into the agricultural sector, while the highest indirect effects result from investing in other agriculture-related sectors such as, for example, food processing. Policy interventions focusing on the agricultural sector and on rural households will thus have the greatest effect on reducing the level of income inequality.     

PREDICTING NEGATIVE EFFECTS OF THE SECOND INTIFADA: AN EX-POST EVALUATION OF SOME MODELS

In 2003, the World Bank (WB), the International Monetary Fund (IMF) and de Boer and Missaglia (DBM) constructed models for the estimation of the 2002 macro-economic indicators of the economy of Palestine. In 2007, IMF and WB provided the consensus estimates of these figures using data that are more up-to-date and more complete than those available in 2003. This note proposes an ex-post evaluation of the predictive performance of the models of WB, DBM and IMF. A comparison of the models of WB and DBM, which are both micro-founded computable general equilibrium models using the same data, reveals that DBM strongly outperforms WB. We argue that the shortening of the time horizon and the quantity adjustment following the dramatic shock explain why our model performs much better. A comparison of DBM with IMF (a simple macro-founded income-expenditure model) also shows that our model performs better.     

MEASURING INTERSECTORAL KNOWLEDGE SPILLOVERS: AN APPLICATION OF SENSITIVITY ANALYSIS TO ITALY

R&D spillovers are unanimously considered as one of the main driving forces of technical change, innovation and economic growth. This paper aims at measuring interindustry R&D spillovers. We apply an ‘uncertainty-sensitivity analysis’ to the Italian input–output table of intermediate goods split into 31 economic sectors for the year 2000. The value added of using this methodology is the opportunity of distinguishing between spillover effects induced by productive linkages (the Leontief forward multipliers) and those activated by R&D investments, capturing the uncertain and non-linear nature of the relations between spillovers and factors affecting them.