Evidence of Convergence Clubs Using Mixture Models

Cross-country economic convergence has been increasingly investigated by finite mixture models. Multiple components in a mixture reflect groups of countries that converge locally. Testing for the number of components is crucial for detecting “convergence clubs.” To assess the number of components of the mixture, we propose a sequential procedure that compares the shape of the hypothesized mixture distribution with the true unknown density, consistently estimated through a kernel estimator. The novelty of our approach is its capability to select the number of components along with a satisfactory fitting of the model. Simulation studies and an empirical application to per capita income distribution across countries testify for the good performance of our approach. A three-clubs convergence seems to emerge.     

Measures of Optimal Centrality: Indicators of City Effect and Urban Overloading

'City-effect' is the peculiar quality of large urban settlements enjoyed by their residents and users. It involves a direct access to special ('superior') urban functions, opportunities and services. This is why it is a very much sought after object of individual and collective aspirations. Large cities concentrate city-effect and often act as powerful magnets in attracting commuters and new residents from surrounding areas, where city-effect is weaker. But when concentration goes beyond a certain threshold, overburdened cities pay for their city-effect in terms of decreasing liveability. Searching for optimal centrality, that is an acceptable trade-off between city effect and decreasing liveability, is among the aims of territorial planning. This paper illustrates a research on the measures of optimal centrality, where social indicators play a key methodological role. It was jointly carried out in four European countries. The indicator-building process is described, and a few points resulting from the study on the operational prerequisites for harmonising and standardising the proposed measures for territorial policies are also offered for reflection.     

A dwindling middle class? Italian evidence in the 2000s

In recent years, increasing attention has been paid to household impoverishment in Italy. Most of previous analyses dealing with this issue are based on summary statistics, which may not capture the whole income distribution. This paper employs a non-parametric tool, the “relative distribution”, to describe patterns of changes in the entire Italian household income distribution over the period 2000–2004. This approach also allows for a decomposition of the relative density to isolate changes due to differences in location from changes due to differences in shape, thus enabling deeper analysis of income polarization. During the 2000s there was a significant location effect, and also increased income polarization, which has particularly affected incomes below the median. Analyses by social groups, according to the employment status of the household head, show significant re-distribution effects within groups.     

Breaking the Stability Pact: Was it predictable?

We show analytically that the credibility problem which has affected the European Stability Pact originates from the insufficient distinction between two reasons for having binding fiscal constraints. The first reason deals with the governments’ tendency to neglect the effects of their fiscal policy on foreign governments (fiscal free-riding). The second reason follows from the governments’ tendency to raise debt by lowering taxes or increasing expenditures, and then to leave it to their successors (fiscal short-termism). An enforcement mechanism relying on governments’ collusion works if the fiscal constraints are not calibrated for curing fiscal short-termism but only for preventing fiscal free-riding.     

A normative justification of compulsory education

Using a household production model of educational choices, we characterise a free-market situation in which some agents (high wagers) fully educate their children and spend a sizable amount of resources on them, while others (low wagers) educate them only partially. The free-market equilibrium is iniquitous, both because the households have different resources and because the children have different access to education. Public policy is thus called for, for vertical as well as horizontal equity purposes. Conventional wisdom has it that both objectives could be achieved using price control instruments, i.e. income taxes and price subsidies. We find instead that income taxes reduce equality of opportunity and that price subsidies cannot remedy this. Quantity controls become necessary: a compulsory education package, financed by a redistributive tax system, achieves both types of equity. Redistributive taxation and compulsory education are therefore best seen as complementary policies.     

Constraining the number of positive responses in adaptive,non-adaptive,and two-stage group testing

Group testing is a well known search problem that consists in detecting the defective members of a set of objects O by performing tests on properly chosen subsets (pools) of the given set O. In classical group testing the goal is to find all defectives by using as few tests as possible. We consider a variant of classical group testing in which one is concerned not only with minimizing the total number of tests but aims also at reducing the number of tests involving defective elements. The rationale behind this search model is that in many practical applications the devices used for the tests are subject to deterioration due to exposure to or interaction with the defective elements. In this paper we consider adaptive, non-adaptive and two-stage group testing. For all three considered scenarios, we derive upper and lower bounds on the number of “yes” responses that must be admitted by any strategy performing at most a certain number t of tests. In particular, for the adaptive case we provide an algorithm that uses a number of “yes” responses that exceeds the given lower bound by a small constant. Interestingly, this bound can be asymptotically attained also by our two-stage algorithm, which is a phenomenon analogous to the one occurring in classical group testing. For the non-adaptive scenario we give almost matching upper and lower bounds on the number of “yes” responses. In particular, we give two constructions both achieving the same asymptotic bound. An interesting feature of one of these constructions is that it is an explicit construction. The bounds for the non-adaptive and the two-stage cases follow from the bounds on the optimal sizes of new variants of d-cover free families and (p, d)-cover free families introduced in this paper, which we believe may be of interest also in other contexts.     

“Judging a book by its cover”: meditation,memory, and invention in seventeenth-century Ukrainian title pages

This article concerns the use of visual paratexts in seventeenth-century Ukraine, and of illustrated title pages in particular. The books under analysis represent three crucial monuments of seventeenth-century Ukrainian sacred oratory. These are: Lazar Baranovych’s Truby sloves propovidnykh na narochityia dni prazdnikov (Kyiv, 1674), and Antonii Radyvylovs'kyi’s Ohorodok Marii Bohorodytsy (Kyiv, 1676) and his Vinets Khrystov z propovidii nedelnykh (Kyiv, 1688). The author concentrates on the “cognitive” aspect of their titular pages, dealing with them as a rhetorical process that emphasizes meditation, invention, and memory. More specifically, she investigates the correlation between the visual and the written as a specific literary-figurative “mode of thought” that stands in a long Christian tradition of expounding images as meditational tools. She shows how Baranovych and Radyvylovs'kyi interact with this tradition, arguing that their title pages provide readers-viewers with both a machina meditativa, a meditative apparatus for reflecting upon the mystery of the Incarnation, and a machina rhetorica, a repertory of images that the users of the books, often themselves preachers, could use to compose new texts.     

A performance counterexample of Billor–Chatterjee–Hadi procedure and an improvement proposal for robust regression

The BCH procedure introduced by Billor, Chatterjee, and Hadi for fitting linear models was found to be inefficient for y-outliers in the presence of a high perturbation level. We propose to modify the first step of the BCH procedure, so that the robust distances are computed on the matrix Z = (y, X) of the basic subset. The performance of the present note procedure (PNP), as compared to the BCH procedure and the ordinary least-square (OLS) method, was studied by processing several datasets used in the literature for robust regression and by performing a Monte Carlo experiment. PNP performs better particularly with datasets having high perturbation.     

Poverty status probability: a new approach to measuring poverty and the progress of the poor

Poverty measurement and the analysis of the progress (or otherwise) of the poor, whether it is societies, families or individuals, is beset with difficulties and controversies surrounding the definition of a poverty line or frontier. Here, borrowing ideas from the mixture model literature, a new approach to assigning poverty-non poverty status is proposed which avoids specifying a frontier, the price is that an agent’s poverty status is only determined to the extent of its chance of being poor. Invoking variants of Gibrat’s law to give structure to the distribution of outcomes for homogeneous subgroups of a population within the context of a finite mixture model of societal outcomes facilitates calculation of an agent’s poverty status probability. From this it is straightforward to calculate all the usual poverty measures as well as other characteristics of the poor and non poor subgroups in a society. These ideas are exemplified in a study of 47 countries in Africa over the recent quarter century which reveals among other things a growing poverty rate and a growing disparity between poor and non poor groups not identified by conventional methods.     

Entering first union: the choice between cohabitation and marriage among women in Italy and Spain

While in Spain and Italy cohabitation has not acquired the same role that it has had in Northern Europe, in both of these Mediterranean countries cohabitation is no longer a marginal phenomenon. Moreover, the nature of cohabiting couples is diverse. According to the most recent FFS data, first cohabitations constitute a temporary arrangement that usually ends in the formalization of the union (marriage), and within 5 years 28.9 % of first cohabitations in Spain and 51.7 % in Italy were transformed into marriages. Within a Western context of changes in union formation patterns, the study of the choice between marriage and cohabitation as first union is of great significance. Is it possible to identify a shared pattern of union formation in Mediterranean countries like Italy and Spain? The purpose of this paper is to examine the choice between cohabitation and marriage as first union (timing, incidence and determinants) using a comparative life course approach. For the analysis of the timing and prevalence, cumulative incidence curves are calculated by birth cohorts and regions; while two semiparametric competing-risks models are estimated for the determinants of first partnership formation (one for each country), considering birth cohort, parental separation, educational attainment, employment status, age at leaving the parental home and birth of a child (the last three time-varying) as independent variables.