Exports versus FDI: An Empirical Test

In a recent paper Helpman, Melitz and Yeaple argue firm heterogeneity leads to self-selection in the structure of international commerce. Only the most productive firms find it profitable to meet the higher costs associated with FDI; the next set of firms finds it profitable to serve foreign markets through exporting; while the least productive firms serve only the domestic market. The paper tests this assumption using the concept of stochastic dominance. Robust support is found for the model, the productivity distribution of multinational firms is found to dominate that of export firms, which in turn dominates that of non-exporters. JEL no. D24, F14, F23     

A STOCHASTIC ESTIMATION FRAMEWORK FOR COMPONENTS OF THE SOUTH AFRICAN CONSUMER PRICE INDEX

Under inflation targeting in South Africa, it is important to monitor and forecast changes in prices, not only for aggregate measures of the consumer price index, but also its underlying sub-components. Hypotheses about sectoral transmission of policy and shocks are often more specific than hypotheses about overall transmission. This study employs a stochastic framework to estimate richly specified equilibrium correction models, four-quarters-ahead, for the 10 sub-components of the first targeted measure of the consumer price index, CPIX. The stochastic trends are estimated by the Kalman filter, and interpreted as capturing structural breaks and institutional change, a frequent cause of forecast failure. The trends suggest the design of deterministic split trends for use in recursive forecasting models, towards more accurate overall inflation forecasting. This research also has practical use for monetary policy in allowing identification of sectoral sources of inflation.     

TAX REFORM AND THE PROGRESSIVITY OF PERSONAL INCOME TAX IN SOUTH AFRICA

This paper investigates the progressivity of personal income tax in South Africa over the period 1989 to 2003. We use the effective, redistributive and disproportionality measures of progressivity and find that progressivity of the tax system increased over the period 1990 to 1994. However, during the first phase of the reform programmes the results are inconclusive with the Kakwani index (disproportionality measure) showing increased progressivity. The redistributive effect measure, on the other hand, indicates a marginal decline in progressivity. During the second phase of the reform programmes, both techniques suggest a worsening in progressivity. One explanation for the decline in progressivity during the latter period in the analysis is the fact that many more “new” taxpayers entered the tax net (higher income groups in our database) which made the distribution of pre‐tax income more unequal thus impacting on progressivity. On the other hand, the disproportionality measure shows a continuous, albeit volatile increase in progressivity over the latter period under investigation.     

Main effects as a by-product in a fixed effect 2 × 2 design,analyzed with ANOVA

To study interaction effects, two sets of data are created for fixed effect ANOVA, both with combinatory effects of the two factors. In the first, both factors and their interaction contribute independently and directly to the dependent variable. In the second, each factor contributes indirectly to the dependent score. Data created with the first model can be analyzed flawlessly. The second often show relatively large main effects and relatively small interaction effects, and as a consequence the interaction effect may be rejected. Even when the dependent variable results solely from the multiplication of both factor scores, highly significant main effects can be obtained, while the interaction effect remains insignificant. Although mathematically correct, the relative contributions of the main effects are in that case difficult to interpret.     

The Impact of Turnout on Turning Up: The Complementarity of Attendance among Co-Workers

This paper studies the effects of complementarities in work attendance on absenteeism. It investigates the case where workers, who turn up for work, cover the workload of absent colleagues. Thus, externalities arise from workers being absent from work. The effort workers exert in the workplace is negatively related to worker turnout. Attendance levels of workers are strategic complements, as workers are more likely to turn up when turnout is high. Firms increase wages and improve working conditions in response. In contrast to the more standard shirking literature, the firm sets employment levels higher. Workers may benefit from draconian firing rules.     

Testing poolability in a system of dynamic regressions with nonspherical disturbances

This study analyzes the testing of cross-equation restrictions within a set of regression equations. Through Monte Carlo experiments we examine the actual size of various asymptotic procedures for testing the poolability hypothesis, i.e., equal slope vectors across individual equations. Regression models with both lagged dependent variable regressors and nonspherical disturbances are considered. In these models we find that the performance in finite samples of classical asymptotic test procedures using critical values from either or ² approximations is often rather poor. However, employing the original test statistics with bootstrapped critical values leads to much more accurate inference in finite samples. In an empirical analysis of panel data on GDP growth and unemployment rates in OECD countries it is shown that classical asymptotic tests and bootstrap procedures may lead to conflicting test outcomes. I am indebted to Peter Boswijk, Jan Kiviet, Peter Vlaar, the associate editor and 2 anonymous referees for their constructive comments. I want to thank Geoffrey Garrett for kindly making available his data.