Inference from PseudoLikelihoods with Plug‐In Estimates

Effective implementation of likelihood inference in models for high‐dimensional data often requires a simplified treatment of nuisance parameters, with these having to be replaced by handy estimates. In addition, the likelihood function may have been simplified by means of a partial specification of the model, as is the case when composite likelihood is used. In such circumstances tests and confidence regions for the parameter of interest may be constructed using Wald type and score type statistics, defined so as to account for nuisance parameter estimation or partial specification of the likelihood. In this paper a general analytical expression for the required asymptotic covariance matrices is derived, and suggestions for obtaining Monte Carlo approximations are presented. The same matrices are involved in a rescaling adjustment of the log likelihood ratio type statistic that we propose. This adjustment restores the usual chi‐squared asymptotic distribution, which is generally invalid after the simplifications considered. The practical implication is that, for a wide variety of likelihoods and nuisance parameter estimates, confidence regions for the parameters of interest are readily computable from the rescaled log likelihood ratio type statistic as well as from the Wald type and score type statistics. Two examples, a measurement error model with full likelihood and a spatial correlation model with pairwise likelihood, illustrate and compare the procedures. Wald type and score type statistics may give rise to confidence regions with unsatisfactory shape in small and moderate samples. In addition to having satisfactory shape, regions based on the rescaled log likelihood ratio type statistic show empirical coverage in reasonable agreement with nominal confidence levels.     

Erratum to: Crime Patterns between Tradition and Change: A Territorial Analysis of the Italian Provinces

Social Indicators Research -     

REPLY TO ULMER: Symbolic Interactionism or A Structural Alternative?

In his critique of our 1999 article "Desensitizing Herbert Blumer's Work on Race Relations: Recent Applications of His Group Position Theory to the Study of Contemporary Race Prejudice,' Jeffery Ulmer charges us with providing a "questionable' interpretation of Blumer's ideas on the grounds that we (1) neglect (or distort) Blumer's advocation for making abstract generalizations in the form of "definitive' concepts, and thus sabotage Blumer's empirical methodology as well as that of symbolic interactionism in general and (2) fail to address a body of literature that deals with "repackaging' Blumer's ideas in such a way that "solves' the sorts of tensions we raise between Blumer's theory and quantitative research. Ulmer fears that our representation of Blumer and symbolic interactionism may result in a host of "mythic facts' (a term borrowed from David Maines) that will undermine Blumer's contributions "to a viable and whole science of the social, including race relations."     

Book reviews

Brezzi Francesca, A Partire dal Gioco ‐ Per i Sentieri di un Pensiero Ludico Marinetti, Genova, 1992, pp. 134, L. 25.000

Ian McIntyre, DOGFIGHT ‐ The Transatlantic Battle over Airbus, Praeger Publishers, 112 pages, $42

Angela Ales Bello, Fenomenología dell'essere umano. Lineamenti di una filosofía al femminile, Roma, Città Nuova, 1992, pp. 170 L. 18.000

“A Critical Note on Some Literature Concerning Backwardness and Social Unbalances in Islamic Countries”     

Employment Illusion,Variable Costs of Migration and Labour Mobility

Why is internal migration in Italy so modest despite the presence of high differentials in employment rates? The paper proposes two different explanations. First, since migration is an investment with non-recoverable costs, it depends not only on the current differential between incomes in the two regions but also on expectations about the same differential in the future. Therefore, the existence of a relatively low differential between adult employment rates is a strong disincentive against migration in the presence of static expectations. The second explanation of the phenomenon is based on the role played by the network costs of migration. If they are important, it is evident that the changes and productive reallocations that have characterized the Italian economy in recent years are important in explaining the decline of migration.     

Migration and the Currency Denomination of Trade

Using a large, transaction‐level dataset of Italian exports and imports with non‐European Union countries, we assess the role of migrants’ networks in shaping the currency denomination of trade. Our results, new to the literature, show sizable, significant effects of migration on the currency denomination of trade. Generally, more migrants lead to more invoicing in the exporter's and importer's currency relative to a vehicle currency, higher educated migrants increase invoicing in the exporter's and importer's currency relative to a vehicle currency, and Italian migrants living in foreign countries have a greater impact relative to foreign migrants living in Italy.     

Estimating Cross Province and Municipal City Price Level Differences in China: Some Experiments and Results

The estimation of Sub-national purchasing power parities (PPPs) for countries where the regions and provinces have different level of development is fundamental for income, consumption, standard of living real term comparisons, as well as for measuring cross-region welfare inequality. This is even truer for large countries like China, where the above aggregates exhibit great variability among provinces. The aim of this paper is to compute the price level differences, measured by the PPPs, for 31 Chinese Provinces and Municipal Cities, based on a sample of 62 goods and services for the year 2014. To our knowledge, this is the first attempt to do it since many years. After a short review of previous studies on China cross-province and municipal cities price level differences measurement and the illustration of methodology and data used, the results of our elaborations are presented and discussed. Taking Beijing as the base area, there is evidence that the PPP max/min ratio is 1.74, confirming the common belief that China cross-province and municipal cities price levels are significantly different.     

Employment status and education/employment relationship of PhD graduates from the University of Ferrara

Two sample surveys of Post-Docs were planned and carried out at the University of Ferrara in 2004 and 2007 aimed at determining the professional status of Post-Docs, the relationship between their PhD education and employment, and their satisfaction with certain aspects of the education and research program. As part of these surveys, two methodological contributions were developed. The first concerns an extension of the non-parametric combination of dependent rankings to construct a synthesis of composite indicators measuring satisfaction with particular aspects of PhD programs [R. Arboretti Giancristofaro and L. Salmaso, Global ranking indicators with application to the evaluation of PhD programs, Atti del Convegno “Valutazione e Customer Satisfaction per la Qualità dei Servizi”, Roma, 8–9 Settembre 2005, pp. 19–22; R. Arboretti Giancristofaro, S. Bonnini, and L. Salmaso, A performance indicator for multivariate data, Quad. Stat. 9 (2007), pp. 1–29; R. Arboretti Giancristofaro, F. Pesarin, and L. Salmaso, Nonparametric approaches for multivariate testing with mixed variables and for ranking on ordered categorical variables with an application to the evaluation of PhD programs, in Real Data Analysis, S. Sawilowsky, ed., a volume in Quantitative Methods in Education and the Behavioral Sciences: Issues, Research and Teaching, Ronald C. Serlin, series ed., Information Age Publishing, Charlotte, North Carolina, 2007, pp. 355–385]. The procedure was applied to highlight differences in the interviewed Post-Docs’ multivariate satisfaction profiles in relation to two aspects: education/employment relationship; employment expectations; and opportunities. The second consists of an inferential procedure providing a solution to the problem of hypothesis testing, where the objective is to compare the heterogeneity of two populations on the basis of sampling data [G.R. Arboretti, S. Bonnini, and F. Pesarin, A permutation approach for testing heterogeneity in two-sample categorical variables, Stat. Comput. (2009) doi: 10.1007/S11222-008-9085-8.]. The procedure was applied to compare the degrees of heterogeneity of Post-Doc judgments in the two surveys with regard to the adequacy of the PhD education for the work carried out.     

Multivariate nonparametric methods in two-way balanced designs: performances and limitations in small samples

Investigations of multivariate population are pretty common in applied researches, and the two-way crossed factorial design is a common design used at the exploratory phase in industrial applications. When assumptions such as multivariate normality and covariance homogeneity are violated, the conventional wisdom is to resort to nonparametric tests for hypotheses testing. In this paper we compare the performances, and in particular the power, of some nonparametric and semi-parametric methods that have been developed in recent years. Specifically, we examined resampling methods and robust versions of classical multivariate analysis of variance (MANOVA) tests. In a simulation study, we generate data sets with different configurations of factor''s effect, number of replicates, number of response variables under null hypothesis, and number of response variables under alternative hypothesis. The objective is to elicit practical advice and guides to practitioners regarding the sensitivity of the tests in the various configurations, the tradeoff between power and type I error, the strategic impact of increasing number of response variables, and the favourable performance of one test when the alternative is sparse. A real case study from an industrial engineering experiment in thermoformed packaging production is used to compare and illustrate the application of the various methods.     

Neurocognitive Effects in Welders Exposed to Aluminium: An Application of the NPC Test and NPC Ranking Methods

The aim of this study is to investigate the effects of exposure to aluminium on the cognitive sphere in a group of welders. Given the intrinsic complexity of the neurocognitive sphere, three different psychomotor variables were used for its investigation allowing the resulting problem to be naturally modelized into a multivariate framework and solved by a nonparametric combination of permutation tests (NPC test). In order to make the treated and control groups comparable, we also stratified the samples on the basis of a risk index that estimates the combined action of biological age and exposure time. Despite the fact that studies in the literature have reached conflicting results, our study highlights a significant drop in attention and memory performances in individuals exposed to aluminium. Finally, we identify a global criterion that summarises the information on the neurocognitive state by applying the nonparametric combination of dependent rankings method (NPC ranking).