Theses towards a new natural philosophy

In this paper I address some philosophical questions regarding the impact quantum mechanics has in the classical conceptions about reality and knowledge. I stress that onto-gnosiological realism still is an option to the issues regarding the relationship between knowledge and reality. Rejecting some radical aspects of Copenhagen interpretation of quantum formalism, I emphasize the advantages of de Broglie’s realistic and causal model. To finish with, I discuss the limits of the Cartesian concept of matter and the split between matter and mind

Bounds and extremal domains for Robin eigenvalues with negative boundary parameter

We present some new bounds for the first Robin eigenvalue with a negative boundary parameter. These include the constant volume problem, where the bounds are based on the shrinking coordinate method, and a proof that in the fixed perimeter case the disk maximises the first eigenvalue for all values of the parameter. This is in contrast with what happens in the constant area problem, where the disk is the maximiser only for small values of the boundary parameter. We also present sharp upper and lower bounds for the first eigenvalue of the ball and spherical shells. These results are complemented by the numerical optimisation of the first four and two eigenvalues in 2 and 3 dimensions, respectively, and an evaluation of the quality of the upper bounds obtained. We also study the bifurcations from the ball as the boundary parameter becomes large (negative).Comment: 26 pages, 20 figure

Individual Teacher Incentives, Student Achievement and Grade Inflation

How do teacher incentives affect student achievement? We contribute to this question by examining the effects of the recent introduction of teacher performance-related pay and tournaments in Portugal's public schools. Specifically, we draw on matched student-school panel data covering the population of secondary school national exams over seven years. We then conduct a difference-in-differences analysis based on two complementary control groups: public schools in two autonomous regions that were exposed to lighter versions of the reform than in the rest of the country; and private schools, which are also subject to the same national exams but whose teachers were not affected by the reform. Our results consistently indicate that the increased focus on individual teacher performance caused a significant decline in student achievement, particularly in terms of national exams. The triple-difference results also document a significant increase in grade inflation.performance-related pay, public sector, matched school-student data

Individual Teacher Incentives, Student Achievement and Grade Inflation

How do teacher incentives affect student achievement? Here we examine the effects of the recent introduction of teacher performance-related pay and tournaments in Portugal's public schools. Specifically, we conduct a difference-in-differences analysis based on population matched student-school panel data and two complementary control groups: public schools in autonomous regions that were exposed to lighter versions of the reform; and private schools, which are subject to the same national exams but whose teachers were not affected by the reform. We find that the focus on individual teacher performance decreased student achievement, particularly in terms of national exams, and increased grade inflation.Tournaments, Public Sector, Matched School-Student Data

Worker Churning and Firms’ Wage Policies

If a random firm were to increase its wages, would that decrease the firm’s churning (“excessive” worker reallocation)? Although the trade-off between wage and churning costs has received attention in both the labour and HRM literatures, there seems to be no evidence about the causal impact of wages upon churning. This paper seeks to fill that gap by considering detailed Portuguese matched employer-employee panel data and different identification methods. After presenting comprehensive evidence about job and worker flows and churning, we find that even models based on within-firm time differences do still generate the negative association between wages and turnover found in most research. However, that result no longer holds when we consider instrumental variables based on minimum wages determined by collective bargaining arrangements. One possible interpretation of our finding is that workers’ effort may not be sufficiently sensitive to wages: employers may replace workers priced out of the labour market with more skilled individuals, so that churning does not fall.Worker Turnover, Endogeneity, Personnel Economics, Efficiency Wages

Can Targeted, Non-Cognitive Skills Programs Improve Achievement? Evidence from EPIS

EPIS is an original and large private-sector program aimed at improving student achievement and eroding early school leaving at Portuguese state schools. The program first screens students to focus only on those more likely to perform poorly; and then conducts a number of small-group sessions aimed at improving the non-cognitive skills (e.g. study skills, motivation, self-esteem) of the selected students. Our quasi-experimental evidence of the effects of EPIS is drawn from rich longitudinal student data and the different timings in the roll-out of the program, both within and across schools. The results indicate that the program reduced grade retention by at least 10 percentage points and did so in a cost effective way.student achievement, program evaluation, matched school-student data

Job separations, heterogeneity, and earnings inequality

Changes in the fraction of workers experiencing job separations can account for> most of the increase in earnings dispersion that occurred both between, as well as> within educational groups in the United States from the mid-1970s to the mid-> 1980s. This is not true of changes in average earnings losses following job separations.> A search model with exogenous human capital accumulation calibrated> to match some selected moments of the U.S. labor market is used to measure the> effects of changes in the fraction of workers experiencing job separations (extensive> margin) versus changes in average earnings losses following job separations> (intensive margin). While both margins do well in accounting for the increase in> the college premium, only the changes in the extensive margin do well in accounting> for the increases in the variance of both the permanent and transitory> components of earnings.Wages ; Income distribution

Paying More to Hire the Best? Foreign Firms, Wages and Worker Mobility

In the context of the debate on the labour-market consequences of globalisation, we examine worker mobility in order to identify the wage differences between foreign and domestic firms. Using matched employer-employee panel data for Portugal, we consider virtually all spells of interfirm mobility over a period of ten years. We find that foreign firms offer significantly more generous wage policies, although there is also a (smaller) selection effect. The results are robust to the consideration of wage growth differences, the case of displaced workers and different subsets of workers.Foreign Direct Investment, Worker Displacement, Wage Growth