Intra-Firm Human Capital Externalities in Tunisia

In this case-study, we use matched worker-firm Tunisian data to elicit the roles of intra-firm human capital and modern firm features in worker remunerations. We show that the estimated return to education in wage equations is not modified when replacing in the list of regressors the firm dummies, representing observed and unobserved firm heterogeneity, by the first three factors of a Principal Component Analysis of the observed firm characteristics. These factors can be interpreted as: the activity sector, the intra-firm human capital density and the modernity of the firm. These results constitute an interesting argument in favour of the presence of intra-firm human capital externalities. Moreover, the estimated education coefficient does not change when the three factors are replaced by three surrogate variables, respectively: the textile industry dummy, the intra-firm mean education, and the firm’s age.economic development, rate of returns, human capital, wage differentials, intra-firm knowledge externalities, Tunisia.

On-the-job learning and earnings: Comparative evidence from Morocco and Senegal.

In this paper, we consider a model of on-the-job learning where workers learn informally by watching and imitating colleagues. We estimate the rate of knowledge diffusion inside the firm using two matched worker-firm data sets from Morocco and Senegal. We rely on non-linear least squares to estimate the structural parameters of the informal learning model and account for firm heterogeneity using firm factors derived from a principal component analysis. We find that the rate of knowledge diffusion is around 7 percent in Morocco and Senegal, but part of the learning-by-watching returns stems from firm heterogeneity. Informal training significantly affects the shape of returns to tenure in these two countries. Finally, we estimate an extended model with both learning-by-watching and learning-by-doing and find significant benefits from imitating colleagues in Morocco.Senegal; Morocco; returns to tenure; learning-by-doing; learning-by-watching; informal training; Earnings functions;

Gender differences in pay in African manufacturing firms

Using matched employer-employee data collected in seven African countries, we present comparative evidence on the magnitude of the gender wage gap in African manufacturing sectors. Using OLS regressions, differences in male and female earnings are found both in Mauritius and Morocco, while the gender wage gap turns out to be insignificant in Benin, Kenya, Madagascar, Senegal and Uganda. Results from quantile regressions indicate that the wage gap remains not constant across the wage distribution. Finally, we study the role of firm characteristics and job segregation across firms as potential factors explaining the gender wage gaps.

Statistical description of turbulent transport for flux driven toroidal plasmas

A novel methodology to analyze non-Gaussian probability distribution functions (PDFs) of intermittent turbulent transport in global full-f gyrokinetic simulations is presented. In this work, the Auto-Regressive Integrated Moving Average (ARIMA) model is applied to time series data of intermittent turbulent heat transport to separate noise and oscillatory trends, allowing for the extraction of non-Gaussian features of the PDFs. It was shown that non-Gaussian tails of the PDFs from first principles based gyrokinetic simulations agree with an analytical estimation based on a two fluid model.Comment: arXiv admin note: text overlap with arXiv:1008.321

Who Suffers the Penalty? A Panel Data Analysis of Earnings Gaps in Vietnam

In spite of its predominant economic weight in developing countries, little is known about informal sector income dynamics vis-à-vis the formal sector. Some works have been done in this field using household surveys, but they only consider some emerging Latin American countries and a few African countries. As a matter of consequence, there is still no way to generalize the (diverging) results to other part of the developing world. Taking advantage of the rich VHLSS dataset in Vietnam, in particular its three waves panel data (2002, 2004, 2006), we assess the magnitude of various formal/informal earnings gaps while addressing heterogeneity issues at three different levels: the worker, the job (wage employment vs. selfemployment) and the earnings distribution.We estimate fixed effects and quantile regressions to control for unobserved individual characteristics. Our results suggest that the informal sector earnings gap highly depends on the workers' job status and on their relative position in the earnings distribution. Penalties may in some cases turn into premiums. By comparing our results with studies in other developing countries, we draw conclusions highlighting the Vietnam's labour market specificity. --informal employment,earnings gap,transition matrix,quantile regressions,panel data,Vietnam

A note on the stationary bootstrap's variance

Because the stationary bootstrap resamples data blocks of random length, this method has been thought to have the largest asymptotic variance among block bootstraps Lahiri [Ann. Statist. 27 (1999) 386--404]. It is shown here that the variance of the stationary bootstrap surprisingly matches that of a block bootstrap based on nonrandom, nonoverlapping blocks. This argument translates the variance expansion into the frequency domain and provides a unified way of determining variances for other block bootstraps. Some previous results on the stationary bootstrap, related to asymptotic relative efficiency and optimal block size, are also updated.Comment: Published in at http://dx.doi.org/10.1214/07-AOS567 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org