Who takes workplace case‐study methods seriously? The influence of gender,academic rank and PhD training

We examine whether differences in the reporting of workplace case‐study research methods are associated with gender, experience, academic rank and PhD training. Using a random sample of published articles, we find that women take more care reporting their research methods in the context of a general increase in methods reporting.     

R&;D: A Small Contribution to Productivity Growth

In this article I evaluate the contribution of R&D investments to productivity growth. The basis for the analysis are the free entry condition and the fact that most R&D innovations are embodied. Free entry yields a relationship between the resources devoted to R&D and the growth rate of technology. Since innovators are small, this relationship is not directly affected by the size of R&D externalities, or the presence of aggregate diminishing returns in R&D after controlling for the growth rate of output and the interest rate. The embodiment of R&D-driven innovations bounds the size of the production externalities. The resulting contribution of R&D to productivity growth in the US is smaller than 3–5 tenths of 1% point. This constitutes an upper bound for the case where innovators internalize the consequences of their R&D investments on the cost of conducting future innovations. From a normative perspective, this analysis implies that, if the innovation technology takes the form assumed in the literature, the actual US R&D intensity may be the socially optimal.     

Gender matters most. The impact on short‐term risk aversion following a financial crash

This paper examines how investors in an emerging market react to a domestic financial crisis. We conjecture that risk aversion increases following such events and that the effect is more pronounced among specific groups of investors. Our study makes use of a unique dataset of mutual fund investors from one of Colombia's largest stock brokers. Our results reveal that women and self‐employed individuals make the largest withdrawals from risky funds after financial crises.     

The codispersion map: a graphical tool to visualize the association between two spatial variables

The codispersion coefficient quantifies the association between two spatial processes for a particular direction (spatial lag) on a two‐dimensional space. When this coefficient is computed for many directions, it is useful to display those values on a single graph. In this article, we suggest a graphical tool called a codispersion map to visualize the spatial correlation between two sequences on a plane. We describe how to construct a codispersion map for regular and non‐regular lattices, providing algorithms in both cases. Three numerical examples are given to illustrate how useful this map can be to detect those directions for which the codispersion coefficient attains its maximum and minimum values. We also provide the R code to construct the codispersion map in practice.     

Are OECD consumption–income ratios stationary after all?

This paper investigates the stochastic properties of the consumption–income ratio for a sample of 23 OECD countries over the period 1960–2005. For that purpose, we employ a battery of recently developed panel unit root and stationarity tests. Our findings from panel unit root tests which do not control for structural breaks appear in line with those from previous studies since they are clearly supportive of the unit root hypothesis. In stark contrast stand the results obtained from the application of a panel stationarity test with multiple breaks, which support the existence of regime-wise stationarity in OECD consumption–income ratios once we control for cross-sectional dependence through bootstrap methods. These findings are reinforced by the median-unbiased estimates of half-lives obtained from impulse-response functions which are found to be finite for the 23 OECD countries.     

A Survey of L1 Regression

L₁ regularization, or regularization with an L₁ penalty, is a popular idea in statistics and machine learning. This paper reviews the concept and application of L₁ regularization for regression. It is not our aim to present a comprehensive list of the utilities of the L₁ penalty in the regression setting. Rather, we focus on what we believe is the set of most representative uses of this regularization technique, which we describe in some detail. Thus, we deal with a number of L₁‐regularized methods for linear regression, generalized linear models, and time series analysis. Although this review targets practice rather than theory, we do give some theoretical details about L₁‐penalized linear regression, usually referred to as the least absolute shrinkage and selection operator (lasso).     

Competitive and core allocations in large economies with differential information

Summary. We study the core and competitive allocations in exchange economies with a continuum of traders and differential information. We show that if the economy is “irreducible”, then a competitive equilibrium, in the sense of Radner (1968, 1982), exists. Moreover, the set of competitive equilibrium allocations coincides with the “private core” (Yannelis, 1991). We also show that the “weak fine core” of an economy coincides with the set of competitive allocations of an associated symmetric information economy in which the traders information is the joint information of all the traders in the original economy. Received March 22, 2000; revised version: May 1, 2000     

ICT employment,over‐education and gender in Spain. Do information and communication technologies improve the female labour situation?

This paper investigates the extent to which ICT‐related employment is improving the labour situation of women in Spain by reducing female over‐education. Outcomes indicate no reduction in female over‐education, nor does a woman's marital status produce any significant differences. However, the best result is observed for ICT occupations linked to higher job quality characteristics.     

The hypothesis of a unit root in OECD inflation revisited

This paper investigates the hypothesis of a unit root in inflation for 13 OECD countries over the period 1957–2005, taking into account cross-sectional dependence and multiple mean shifts. We conduct unit root testing with the more powerful unit root tests with cross-dependence proposed by Smith et al. [Smith, L. V., Leybourne, S., Kim, T., & Newbold, P. (2004). More powerful panel data unit root tests with an application to the mean reversion in real exchange rates. Journal of Applied Econometrics, 19(2), 147–170] and a bootstrap version of the panel stationarity test of Hadri [Hadri, K. (2000). Testing for stationarity in heterogeneous panel data. The Econometrics Journal, 3(2), 148–161.], which provide inconclusive evidence on the time series properties of OECD inflation rates. To shed some light on this issue, we employ the recently developed panel stationarity test of Carrión-i-Silvestre et al. [Carrión-i-Silvestre, J. L., Del Barrio, T., & López-Bazo, E. (2005). Breaking the panels: An application to the GDP per capita. The Econometrics Journal, 8(2), 159–175] that assumes a highly flexible trend function by incorporating an unknown number of breaks in level. Overall, our confirmatory analysis renders clear-cut evidence in favor of regime-wise stationarity. Furthermore, the breaks in inflation detected are closely associated with macroeconomic shocks and changes in monetary policy.