In this dissertation we proposed two generalizations of the Second-Order Least Squares (SLS) approach in two popular dynamic econometrics models. The first one is the regression model with time varying nonlinear mean function and autoregressive conditionally heteroskedastic (ARCH) disturbances. The second one is a linear dynamic panel data model. We used a semiparametric framework in both models where the SLS approach is based only on the first two conditional moments of response variable given the explanatory variables. There is no need to specify the distribution of the error components in both models. For the ARCH model under the assumption of strong-mixing process with finite moments of some order, we established the strong consistency and asymptotic normality of the SLS estimator. It is shown that the optimal SLS estimator, which makes use of the additional information inherent in the conditional skewness and kurtosis of the process, is superior to the commonly used quasi-MLE, and the efficiency gain is significant when the underlying distribution is asymmetric. Moreover, our large scale simulation studies showed that the optimal SLSE behaves better than the corresponding estimating function estimator in finite sample situation. The practical usefulness of the optimal SLSE was tested by an empirical example on the U.K. Inflation. For the linear dynamic panel data model, we showed that the SLS estimator is consistent and asymptotically normal for large N and finite T under fairly general regularity conditions. Moreover, we showed that the optimal SLS estimator reaches a semiparametric efficiency bound. A specification test was developed for the first time to be used whenever the SLS is applied to real data. Our Monte Carlo simulations showed that the optimal SLS estimator performs satisfactorily in finite sample situations compared to the first-differenced GMM and the random effects pseudo ML estimators. The results apply under stationary/nonstationary process and wih/out exogenous regressors. The performance of the optimal SLS is robust under near-unit root case. Finally, the practical usefulness of the optimal SLSE was examined by an empirical study on the U.S. airfares.

This thesis examined an ability of the scoreboard indicators created by the European Commission to capture macroeconomic imbalances expressed as the changes of GDP. We conducted an empirical analysis for panel data of 27 EU countries in the 1997-2011 period. We adopted three different dynamic panel data models based on the three estimators: the Arrelano- Bond, the Arrelano-Bover and the corrected LSDV estimator. Our results suggest that despite some bad characteristics of our dataset we can conclude that some of the indicators such as 3- year average of current account balance or percentage change in export market shares seem to be inadequate for measuring the imbalances. Moreover, the indicators were proved not to be able to predict an occurrence of imbalances.

<p>This thesis consists of a summary and four papers. The first two concerns health care and sickness absence, and the last two pharmaceutical costs and prices.</p><p>Paper [I] presents an economic federation model which resembles the situation in, for example, Sweden. In the model the state governments provide health care, the fed-eral government provides a sickness benefit and both levels tax labor income. The re-sults show that the states can have either an incentive to under- or over-provide health care. The federal government can, by introducing an intergovernmental transfer, in-duce the state governments to provide the socially optimal amount of health care.</p><p>In Paper [II] the effect of aggregated public health care expenditure on absence from work due to sickness or disability was estimated. The analysis was based on data from a panel of the Swedish municipalities for the period 1993-2004. Public health care expenditure was found to have no statistically significant effect on absence and the standard errors were small enough to rule out all but a minimal effect. The result held when separate estimations were conducted for women and men, and for absence due to sickness and disability.</p><p>The purpose of Paper [III] was to study the effects of the introduction of fixed pharmaceutical budgets for two health centers in Västerbotten, Sweden. Estimation results using propensity score matching methods show that there are no systematic differences for either price or quantity per prescription between health centers using fixed and open-ended budgets. The analysis was based on individual prescription data from the two health centers and a control group both before and after the introduction of fixed budgets.</p><p>In Paper [IV] the introduction of the Swedish substitution reform in October 2002 was used as a natural experiment to examine the effects of increased consumer infor-mation on pharmaceutical prices. Using monthly data on individual pharmaceutical prices, the average reduction of prices due to the reform was estimated to four percent for both brand name and generic pharmaceuticals during the first four years after the reform. The results also show that the price adjustment was not instant.</p>

This thesis consists of a summary and four papers. The first two concerns health care and sickness absence, and the last two pharmaceutical costs and prices. Paper [I] presents an economic federation model which resembles the situation in, for example, Sweden. In the model the state governments provide health care, the fed-eral government provides a sickness benefit and both levels tax labor income. The re-sults show that the states can have either an incentive to under- or over-provide health care. The federal government can, by introducing an intergovernmental transfer, in-duce the state governments to provide the socially optimal amount of health care. In Paper [II] the effect of aggregated public health care expenditure on absence from work due to sickness or disability was estimated. The analysis was based on data from a panel of the Swedish municipalities for the period 1993-2004. Public health care expenditure was found to have no statistically significant effect on absence and the standard errors were small enough to rule out all but a minimal effect. The result held when separate estimations were conducted for women and men, and for absence due to sickness and disability. The purpose of Paper [III] was to study the effects of the introduction of fixed pharmaceutical budgets for two health centers in Västerbotten, Sweden. Estimation results using propensity score matching methods show that there are no systematic differences for either price or quantity per prescription between health centers using fixed and open-ended budgets. The analysis was based on individual prescription data from the two health centers and a control group both before and after the introduction of fixed budgets. In Paper [IV] the introduction of the Swedish substitution reform in October 2002 was used as a natural experiment to examine the effects of increased consumer infor-mation on pharmaceutical prices. Using monthly data on individual pharmaceutical prices, the average reduction of prices due to the reform was estimated to four percent for both brand name and generic pharmaceuticals during the first four years after the reform. The results also show that the price adjustment was not instant.

El proceso de apertura comercial experimentado por Argentina en los años 90 sometió a la industria por primera vez en mucho tiempo a la competencia externa. Este trabajo investiga en qué medida la competencia externa potencial actuó como un limitante del poder de mercado de la industria local. Utilizando modelos dinámicos para datos en panel se demostró que dicha competencia fue significativa durante el período 1995-2001. En particular, algunos de los modelos estimados sugieren que aquellas industrias menos concentradas, con menor protección arancelaria, con economías de escala más reducidas, no vinculadas directamente a la actividad agropecuaria o que producen productos menos diferenciados son las que enfrentaron una competencia potencial externa significativa. / The process of trade liberalization experienced by Argentina in the 90s subjected domestic industries to foreign competition for the first time in many years. This paper studies to what extent potential foreign competition was a limiting factor of domestic market power. Using dynamic panel data models, this paper shows that such competition was significant between 1995 and 2001. Specifically, some of the models suggest that those industries not directly linked to agricultural activities, with a low degree of concentration, with low tariff barriers, with a low degree of economies of scale and whose output has a low degree of differentiation are the ones that experienced significant potential foreign competition. / Una versión de este trabajo obtuvo el premio "Elías Salama" otorgado en las X Jornadas de Economía Monetaria e Internacional, organizadas por el Departamento de Economía de la Universidad Nacional de La Plata.

The study aims to investigate the impact of natural resource wealth on the shadow economy. The theoretical section provides the basis of understanding the nature of two phenomena and discusses the possible transmission channels through which natural resources might influence the shadow economy. Consequently, the key determinants of the shadow economy are examined by static and dynamic models. Natural resource abundance is proxied by natural resource rents. We employ a panel data set for 109 countries for the period from 1996 to 2006. The results reveal that resource wealth is associated with the decrease of the shadow economy. This result is robust for different resource types (durable and non-durable), and the effect is more profound for countries with a low income level. JEL Classification C33, E26, O13 Keywords natural resources, shadow economy, dynamic panel data models, system GMM estimator Title Natural Resource Curse and Shadow Economy: Empirical Evidence

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