Javier Ruiz-Castillo

This paper presents an algorithm based on the bootstrap to select an admissible aggregation level, that is, the minimum number of occupational categories which yield a gender segregation value which is not significantly smaller than that obtained from the large number of occupational categories usually available in any data set. The approach is illustrated using Labor Force Survey data for Spain for the comparison of gender segregation in 1977 and 1992, as well as 1994 and 2000. To measure gender segregation, an additively decomposable segregation index based in the entropy concept is used. Despite a substantial simplification in the size of the occupation’s space, the decrease in the segregation index is very small and not significant, regardless of the year. Consequently, intertemporal changes in gender segregation can be studied using a greatly reduced classification of occupations that permits an easier interpretation of results.

In Spain, recruiting and promotion procedures in the public sector would appear to leave less room for gender discrimination than in the private sector. Employing data for 1977 and 1992, this paper explores the consequences of these procedures for gender segregation using an additively decomposable segregation index based on the entropy concept. It is found that gender segregation in the private sector is significantly larger than in the public sector in both years. Furthermore, segregation remains constant in the public sector but increases by 15% in the private sector throughout the period. Finally, the index decomposability property is used to highlight the role of public hiring procedures in gender segregation differences.

This paper compares the average productivity of those in brain drain (migrants), brain circulation (temporary migrants) and stayers (whose entire career takes place in their country of origin) in a set of 2,530 highly productive economists that work in 2007 in a selection of the top 81 Economics departments worldwide. There are three main findings. Firstly, among nationals from the eleven countries other than the U.S. with at least one department in the sample, migrants are positively selected relative to stayers –exacerbating the brain drain problem from the sending countries point of view. Moreover, those in brain circulation are negatively selected relative to those brain-drained into the U.S. but are also generally more productive than stayers. Secondly, among U.S. nationals, the ranking is very different: brain circulation, followed by stayers, and brain drain. From a global point of view, the selection effects summarized in these two points can be seen as contributing to the best allocation of resources. Thirdly, comparisons between the average productivity of foreigners and stayers in a given geographical area are very much affected by two factors: the quality threshold that defines the base to which foreigners are compared, and the type of department where comparisons take place in a partition into five department categories. For example, in the bottom 56 departments foreigners are more productive than stayers in the total sample, but the two groups are indistinguishable in an elite consisting of 833 economists with above average productivity. In the top 25 U.S. departments the two groups are equally productive, both in the total sample and in the elite.

Este artículo defiende que aunque 1:1 noción de pobreza absoluta aún debe ser un
ingrediente esencial en la evaluación de la calidad de vida de los países en desarrollo
yen transición, es hora de que la pobreza relativa comience a ser sistemáticamente
estimada para esos mismos países. Esta recomendación se aplica a México durante el
periodo 1992-2004, cuando en 2000 el gobierno de Fox determinó oficialmente por
primera vez una línea de pobreza absoluta. Como en el Segundo Programa Europeo
de Pobreza a fines de los años ochenta, la línea de pobreza relativa se fija en 50% de la
media del gasto equivalente. Las pobrezas absoluta y la relativa se comportan de
maneras opuestas durante el ciclo 1992-2000, pero ambas descienden significativamente
durante el periodo de estancamiento 2000-2004. La pobreza relativa es
mayor que la absoluta desde 1992 a 1994, menor en 1996-1998 y mayor de nuevo en
2000-2004. En cualquier caso, la pobreza relativa en México es mucho mayor que
la pobreza reiativa en los países desarrollados.

This paper employs the theory of equality of opportunity, described in Roemer’s book
(Equality of Opportunity, Harvard University Press, 1998), to compute the extent to which
tax-and-transfer regimes in 11 countries equalize opportunities among citizens for income
acquisition. Roughly speaking, equality of opportunity for incomes has been achieved in a
country when it is the case that the distributions of post-fisc income are the same for
different types of citizen, where a citizen’s type is defined by the socio-economic status of
his parents. Intuitively, a country will have equalized opportunity if the chances of earning
high (or low) income are equal for citizens from all family backgrounds. Of course, pre-fisc
income distributions, by type, will not be identical, as long as the educational system does not entirely make up for the disadvantage that children, who come from poor families face,
but the tax-and-transfer system can play a role in rectifying that inequality. We include, in
our computation, two numbers that summarize the extent to which each country’s current
fiscal regime achieves equalization of opportunities for income, and the deadweight loss
that would be incurred by moving to the regime that does.

Recent research has shown that two entropy-based segregation
indices possess an appealing mixture of basic and subsidiary but
useful properties. It would appear that the only fundamental difference
between the mutual information orMindex, and the entropy
information or H index, is that the second is a normalized version
of the first. This paper introduces another normalized index in
that family, the H∗ index, which captures segregation as the tendency
of racial groups to have different distributions across schools.
More importantly, the paper shows that applied researchers may
do better using the M index than using either H or H∗ in two
circumstances: (1) if they are interested in the decomposability
of the measurement of segregation, and (2) if they are interested
in a margin-free measurement of segregation changes. The shortcomings
of the H and H∗ indices are illustrated below by means
of numerical examples, as well as with school segregation data by
ethnic group in the U.S. public school system between 1989 and
2005.

This paper studies evidence from Thomson Scientific about the citation process of 3.7 million articles published in the period 1998-2002 in 219 Web of Science categories, or sub-fields. Reference and citation distributions have very different characteristics across sub-fields. However, when analyzed with the Characteristic Scores and Scales technique, which is replication and scale invariant, the shape of these distributions over three broad categories of articles appears strikingly similar. Reference distributions are mildly skewed, but citation distributions with a five-year citation window are highly skewed: the mean is twenty points above the median, while 9-10% of all articles in the upper tail account for about 44% of all citations. The aggregation of sub-fields into disciplines and fields according to several aggregation schemes preserve this feature of citation distributions. It should be noted that when we look into subsets of articles within the lower and upper tails of citation distributions the universality partially breaks down. On the other hand, for 140 of the 219 sub-fields the existence of a power law cannot be rejected. However, contrary to what is generally believed, at the sub-field level the scaling parameter is above 3.5 most of the time, and power laws are relatively small: on average, they represent 2% of all articles and account for 13.5% of all citations. The results of the aggregation into disciplines and fields reveal that power law algebra is a subtle phenomenon.

This paper studies evidence from Thomson Scientific about the citation process of 3.7 million articles published in the period 1998-2002 in 219 Web of Science categories, or sub-fields. Reference and citation distributions have very different characteristics across sub-fields. However, when analyzed with the Characteristic Scores and Scales technique, which is size and scale independent, the shape of these distributions appear extraordinarily similar. Reference distributions are mildly skewed, but citation distributions with a five-year citation window are highly skewed: the mean is twenty points above the median, while 9-10% of all articles in the upper tail account for about 44% of all citations. The aggregation of sub-fields into disciplines and fields according to several aggregation schemes preserve this feature of citation distributions. On the other hand, for 140 of the 219 sub-fields the existence of a power law cannot be rejected. However, contrary to what is generally beli...

This paper reviews scientific excellence in 38 countries and eight geographical areas using two sets of novel indicators of citation impact: a family of high-impact indicators imported from the poverty literature in Economics, and a set of indicators within the percentile rank approach. Among the main findings with a dataset of about 4.4 million from Thomson Scientific we emphasize the following three. (i) The proportion 10%, and two important percentile rank indicators bring no novelty relative to a traditional average-based indicator. (ii) A high-impact indicator very sensitive to citation inequality is seen to be useful to detect success at a local level, but not for a global ranking that includes small research units. (iii) A monotonic high-impact indicator sensitive to any increase in citations is used to rank the partition of the world into 46 units in the 22 broad fields distinguished by Thomson Scientific, as well as the all-sciences case. The authors acknowledge financial support by Santander Universities Global Division of Banco Santander. Albarrán acknowledges additional financial support from the Spanish MEC through grants ECO2009-11165 y ECO2011-29751, and Ruiz-Castillo through grant SEJ2007-67436. This paper is produced as part of the project Science, Innovation, Firms and markets in a Globalised World (SCIFIGLOW), a Collaborative Project funded by the European Commission's Seventh Research Framework Programme, Contract number SSH7-CT-2008-217436.