The Granular Origins of Aggregate Fluctuations

This paper proposes that idiosyncratic firm‐level shocks can explain an important part of aggregate movements and provide a microfoundation for aggregate shocks. Existing research has focused on using aggregate shocks to explain business cycles, arguing that individual firm shocks average out in the aggregate. I show that this argument breaks down if the distribution of firm sizes is fat‐tailed, as documented empirically. The idiosyncratic movements of the largest 100 firms in the United States appear to explain about one‐third of variations in output growth. This “granular” hypothesis suggests new directions for macroeconomic research, in particular that macroeconomic questions can be clarified by looking at the behavior of large firms. This paper's ideas and analytical results may also be useful for thinking about the fluctuations of other economic aggregates, such as exports or the trade balance.     

Strategic Supply Function Competition With Private Information

A finite number of sellers (n) compete in schedules to supply an elastic demand. The cost of each seller is random, with common and private value components, and the seller receives a private signal about it. A Bayesian supply function equilibrium is characterized: The equilibrium is privately revealing and the incentives to rely on private signals are preserved. Supply functions are steeper with higher correlation among the cost parameters. For high (positive) correlation, supply functions are downward sloping, price is above the Cournot level, and as we approach the common value case, price tends to the collusive level. As correlation becomes maximally negative, we approach the competitive outcome. With positive correlation, private information coupled with strategic behavior induces additional distortionary market power above full information levels. Efficiency can be restored with appropriate subsidy schemes or with a precise enough public signal about the common value component. As the market grows large with the number of sellers, the equilibrium becomes price‐taking, bid shading is on the order of 1/n, and the order of magnitude of welfare losses is 1/n². The results extend to inelastic demand, demand uncertainty, and demand schedule competition. A range of applications in product and financial markets is presented.     

The Sichel model and the mixing and truncation order

The analysis of word frequency count data can be very useful in authorship attribution problems. Zero-truncated generalized inverse Gaussian–Poisson mixture models are very helpful in the analysis of these kinds of data because their model-mixing density estimates can be used as estimates of the density of the word frequencies of the vocabulary. It is found that this model provides excellent fits for the word frequency counts of very long texts, where the truncated inverse Gaussian–Poisson special case fails because it does not allow for the large degree of over-dispersion in the data. The role played by the three parameters of this truncated GIG-Poisson model is also explored. Our second goal is to compare the fit of the truncated GIG-Poisson mixture model with the fit of the model that results from switching the order of the mixing and truncation stages. A heuristic interpretation of the mixing distribution estimates obtained under this alternative GIG-truncated Poisson mixture model is also provided.     

Selecting significant effects in factorial designs: Lenth's method versus using negligible interactions

Among the many analytical techniques that have been published to analyze the significance of the effects in the absence of replications, two have emerged as the most widely used in text books as well as statistical software packages: The Lenth's method and the estimation of the variance of the effects from the values of those considered negligible. This article shows that neither is better than the other in all cases, and by analyzing the results obtained in a wide variety of situations it provides guidelines on when it is preferable to use one or the other technique.     

A breakpoint detection in the mean model with heterogeneous variance on fixed time intervals

Statistics and Computing - This work is motivated by an application for the homogenization of global navigation satellite system (GNSS)-derived integrated water vapour series. Indeed, these series...     

Social cohesion revisited: a new definition and how to characterize it

This paper provides a general overview on different perspectives and studies on social cohesion, offers a definition of social cohesion that is deeply rooted in current literature, and provides a framework that can be used to characterize social cohesion and help support resilient cities. The framework highlights the factors that play a substantial role in enabling social cohesion, and shows from which perspectives it can be fostered.     

Labour incorporation of young Southern European graduates in Mexico: the impact of the economic crisis

ABSTRACT

The 2008 economic crisis has had particularly negative effects on the youth labour market outcomes in Southern Europe. Thus, it is hardly surprising that many Southern European youngsters see migration as the only way to escape from under-employment and precariousness. In this context, the article studies the reasons for emigration to Mexico of a group of young graduates from Italy and Spain. The paper is based on 42 in-depth semi-structured interviews with young graduates, aged 29 years old or less on their arrival in Mexico. The article first explores the relevance of the economic crisis as the main reason behind the migration of this group. It is revealed that the interviewed graduates had a precarious labour incorporation back in their countries of origin, and migration appeared as a means to further their careers. Second, the paper analyses the interviewees’ labour incorporation in Mexico; in many cases this coincides with an extended university-work transition, since many of them had not secured full-time permanent jobs before their arrival in Mexico. Finally, the paper explores the interviewees’ future plans. These depend not only on their work experiences in Mexico but also on their degree of social and cultural integration in the host country.     

Youth earnings and labour market volatility in Europe

The authors provide new evidence on youth earnings and labour market volatility, including flows into and out of employment, across Europe during the Great Recession. EU‐SILC data for the period 2004–13 reveal large disparities in volatility levels and trends across European countries. As expected, the Great Recession increased youth labour market volatility, offsetting the trends observed over the previous years of economic prosperity. A variance decomposition exercise points to greater exposure to worker turnover in southern Europe. Fixed effects regression on labour market institutions relates higher unemployment benefits and more stringent employment protection legislation to lower earnings and labour market volatility.