Institutions and firm formation: An empirical analysis of Portuguese municipalities

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Hospital costs and random demand

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

The impact of sizeof the firm and exchange rate in the export propensity of domestic and foreign owned firms in a developing country: A study of the Brazilian exporters

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Determinants of export diversification and sophistication in sub-saharan Africa

This paper studies the political and economic factors that determine successful export diversification (ED) and export sophistication (ES) strategies in the Sub-Saharan African (SSA) countries and also the way in which successful ED and sophistication strategies contribute to explain the improving in some of the millennium development goals (MDG). We run separate regressions for the determinants of ES and ED, using disaggregated data of the 48 SSA countries, from 1960 to 2005. The results suggest that better governance is an important determinant for the success of diversification and sophistication strategies in SSA. In particular the level of corruption, transparency and accountability are important factors in limiting or promoting the scope of diversification and the level of sophistication of the exports. The results also suggest that increases in human capital in SSA countries promote both ED and ES, showing that the level of education of the workforce is positively related with ES and ED, with higher levels of education (tertiary) playing a more important role in explaining ES, while lower levels of education (primary) being more important as determinants of ED. In the second part we explore the links between ED and ES and growth presenting evidence that ED and ES are linked to growth stability in SSA. This study also suggests that the Sub-Saharan countries that were more successful in achieving ED and ES tend to be more successful in improving the living conditions of their population. Using different variables of Infant Mortality (one of the MDG) and life expectancy as dependent variables, we present evidence that suggests that in SSA higher ED and ES are associated with lower infant mortality and higher life expectancy. We show that this result is robust, presenting positive and significant results even when a large number of different control variables are introduced, or when fixed effects and instrumental variables are considered. The evidence suggests that ED and ES are part of the solution for a successful development of SSA.

Government bond yield spreads in EMU countries: The story of an ephemeral convergence

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Cost efficiency in the Portuguese water sector: The case of multimunicipal systems operating at the bulk level

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Democracy and fertility

A Masters Thesis, presented as part of the requirements for the award of a Research Masters Degree in Economics from NOVA – School of Business and Economics

Is low worker mobility evidence for monopsony power?

Major in Competition and Regulation

Health systems efficiency after the crisis in the OECD

This work evaluates the efficiency position of the health system of each OECD country. It identifies whether, or not, health systems changed in terms of quality and performance after the financial crisis. The health systems performance was calculated by fixed-effects estimator and by stochastic frontier analysis. The results suggest that many of those countries that the crisis affected the most are more efficient than the OECD average. In addition, some of those countries even managed to reach the top decile in the efficiency ranking. Finally, we analyze the stochastic frontier efficiency scores together with other health indicators to evaluate the health systems’ overall adjustments derived from the crisis.

Practice variations in the production of health

This study investigates three questions related to medical practice variation. First, it tests whether average length of stay across Portuguese National Health Service hospitals varies when controlling for differences in patients’ characteristics. Second, it looks at hospital-level characteristics in order to find out whether these are able to explain differences in average length of stay across hospitals. Finally, it proposes a best practice average length of stay for each of the six episodes of care analyzed. To perform the analysis, administrative data from the Diagnosis-Related groups’ data set for the year of 2012 was used. A replication of a hierarchical two-stage model with hospital fixed effects was carried out. The results show that after taking patients’ characteristics into account, variation in average length of stay across hospitals exists. This variation cannot be explained by hospital-level characteristics.

Bias in returns to tenure when firm wages and employment comove: A quantitative assessment and solution

It is well known that, unless worker-firm match quality is controlled for, returns to firm tenure (RTT) estimated directly via reduced form wage (Mincer) equations will be biased. In this paper we show that even if match quality is properly controlled for there is a further pervasive source of bias, namely the co-movement of firm employment and firm wages. In a simple mechanical model where human capital is absent and separation is exogenous we show that positively covarying shocks (either aggregate or firm level) to firms employment and wages cause downward bias in OLS regression estimates of RTT. We show that the long established procedures for dealing with "traditional" RTT bias do not circumvent the additional problem we have identified. We argue that if a reduced form estimation of RTT is undertaken, firm-year fixed effects must be added in order to eliminate this bias. Estimates from two large panel datasets from Portugal and Germany show that the bias is empirically important. Adding firm-year fixed effects to the regression increases estimates of RTT in the two respective countries by between 3.5% and 4.5% of wages at 20 years of tenure over 80% (50%) of the estimated RTT level itself. The results extend to tenure correlates used in macroeconomics such as the minimum unemployment rate since joining the firm. Adding firm-year fixed effects changes estimates of these effects also.

O impacto da gestão de fundo de maneio na rendibilidade das empresas durante a crise financeira: evidência europeia

Dissertação de mestrado em Finanças

The Effect of relationship lending on firm performance

We examine how relationship lending affects firm performance using a panel dataset of about 70,000 small and medium Spanish firms in the period 1993-2004. We model firm performance jointly with the firm's choice of the number of bank relationships. Controlling for firm fixed effects and using instrumental variables for the decision on the number of bank relationships, we find that firms maintaining exclusive bank relationships have lower profitability. The result is consistent with the view that banks appropriate most of the value generated through close relationships with its borrowers as long as they do not face competition from other lenders.

Correlation of wear in vivo and six laboratory wear methods.

OBJECTIVE: We examined the correlation between clinical wear rates of restorative materials and enamel (TRAC Research Foundation, Provo, USA) and the results of six laboratory test methods (ACTA, Alabama (generalized, localized), Ivoclar (vertical, volumetric), Munich, OHSU (abrasion, attrition), Zurich). METHODS: Individual clinical wear data were available from clinical trials that were conducted by TRAC Research Foundation (formerly CRA) together with general practitioners. For each of the n=28 materials (21 composite resins for intra-coronal restorations [20 direct and 1 indirect], 5 resin materials for crowns, 1 amalgam, enamel) a minimum of 30 restorations had been placed in posterior teeth, mainly molars. The recall intervals were up to 5 years with the majority of materials (n=27) being monitored, however, only for up to 2 years. For the laboratory data, the databases MEDLINE and IADR abstracts were searched for wear data on materials which were also clinically tested by TRAC Research Foundation. Only those data for which the same test parameters (e.g. number of cycles, loading force, type of antagonist) had been published were included in the study. A different quantity of data was available for each laboratory method: Ivoclar (n=22), Zurich (n=20), Alabama (n=17), OHSU and ACTA (n=12), Munich (n=7). The clinical results were summed up in an index and a linear mixed model was fitted to the log wear measurements including the following factors: material, time (0.5, 1, 2 and 3 years), tooth (premolar/molar) and gender (male/female) as fixed effects, and patient as random effect. Relative ranks were created for each material and method; the same was performed with the clinical results. RESULTS: The mean age of the subjects was 40 (±12) years. The materials had been mostly applied in molars (81%) and 95% of the intracoronal restorations were Class II restorations. The mean number of individual wear data per material was 25 (range 14-42). The mean coefficient of variation of clinical wear data was 53%. The only significant correlation was reached by OHSU (abrasion) with a Spearman r of 0.86 (p=0.001). Zurich, ACTA, Alabama generalized wear and Ivoclar (volume) had correlation coefficients between 0.3 and 0.4. For Zurich, Alabama generalized wear and Munich, the correlation coefficient improved if only composites for direct use were taken into consideration. The combination of different laboratory methods did not significantly improve the correlation. SIGNIFICANCE: The clinical wear of composite resins is mainly dependent on differences between patients and less on the differences between materials. Laboratory methods to test conventional resins for wear are therefore less important, especially since most of them do not reflect the clinical wear.

Industrial districts, innovation and I-district

The I-district effect hypothesis establishes the existence of highly intense innovation in Marshallian industrial districts due to the presence of external localization economies. However, industrial districts are characterized by specific manufacturing specializations in such a way that this effect could be due to these dominant specializations. The objective of this research is to test whether the effect is explained by the conditions of the territory or by the industrial specialization and to provide additional evidence of the existence and causes of the highly intense innovation in industrial districts (I-district effect). The estimates for Spain of a fixed effects model interacting territory and industry suggest that the high innovative performance of industrial districts is maintained across sectors whereas the industrial specialization behaves differently depending on the type of local production system in which it is placed. The I-district effect is related to the conditions of the territory more than to the industrial specialization. The territory is a key variable in explaining the processes of innovation and should be considered a basic dimension in the design of innovation and industrial policies.