Proença, IsabelSantos, Luís Filipe Ávila da Silveira dos2020-12-092020-12-092020-07Santos, Luís Filipe Ávila da Silveira dos (2020). "Essays in Spatial Econometrics". Tese de Doutoramento, Universidade de Lisboa. Instituto Superior de Economia e Gestão.http://hdl.handle.net/10400.5/20625Doutoramento em Matemática Aplicada à Economia e GestãoThis thesis addresses the specification and estimation of Spatial Lag Models for dichotomous or fractional responses. Three essays are presented. The first essay suggests a new method to approximate the inverse of the spatial lag operator, used in the estimation of Spatial Lag Models for binary outcomes. Related matrix operations are approximated, as well. Closed formulas for the elements of the approximated matrices are deduced. Computational time and complexity is greatly reduced. The second essay focus on the specification of Spatial Lag Models for fractional responses. Observations at the corners, zero and one, are allowed. Two specifications are proposed. The Fractional Response Spatial Lag Model (FRSLM), extends the seminal approach of Papke and Wooldridge (1996) to spatial frameworks. The approximate Fractional Response Spatial Lag Model (aFRSLM), allows to write the FRSLM as an approximate reduced form. Of particular relevance is the interpretation of policy effects. The third essay extends the second essay to the panel data setting. The individual unobserved effects are allowed to be correlated with the explanatory variables. The treatment of the unobserved heterogeneity is addressed as a central issue. Estimation is based on an iterative Generalized Method of Moments (iGMM) procedure, with well-known instruments. Inference is robust to spatial heteroskedasticity and spatial autocorrelation. The performance of the iGMM estimator is evaluated through detailed simulation studies. Results show that the iGMM estimator tends to perform well in terms of computational time, accuracy and precision. The adequacy of the proposed approaches is also assessed through empirical applications on the U.S. Metropolitan Statistical Areas. The first essay analyzes environmental effects over regional competitiveness and the degree of competitiveness spillovers. A new definition for binary competitiveness is introduced. Results show that competitiveness is significantly affected by air quality. Also, being competitive plays an important role in the competitiveness of neighboring areas. The third essay discusses regional knowledge and innovation spillovers, based on the proportion of high-tech patents. Results show that human capital plays a major role in regional innovative processes. However, due to regional aggregation, the degree of knowledge spillovers is significantly low.engdoctoral thesis