1,720,967 research outputs found
Measurement Error Issues in Consumption Data
Get PDFData available in commonly employed consumer surveys, like the \emph{Consumer Expenditure Survey} in the US, are widely known to be affected by measurement errors. Ignoring the effect of such errors in the estimation of consumption models may result in severely biased estimates of the quantities of interest. In this thesis I consider identification of three different models of consumption behavior allowing for the presence of measurement errors.
Identification is particularly difficult to achieve due to the high non-linearity of the specifications involved and to peculiarities of consumptions models. In fact in many instances, allowing for mismeasured covariates also implies correlated measurement errors also in the dependent variable. This further complicates the identification of the model, invalidating most of the non-linear errors in variables results in the literature.
The core of the thesis is made of three Chapters. In the first Chapter I consider identification of a particular specification of Engel curves when unobserved expenditure is endogenous and measured with error. In the second Chapter I study identification of a general non-linear errors in variables model allowing for correlated measurement errors on both sides of the equation. In the third Chapter I derive identification and estimation of the distribution of consumption when only expenditure and the number purchases are observed.I dati disponibili nelle più comuni indagini sui consumatori, come la Consumer Expenditure Survey negli Stati Uniti, sono noti per essere affetti da errori di misura. Ignorare l'effetto di questi errori nella stima di modelli di consumo può portare a stime distorte delle quantità di interesse. Questa tesi discute l'identificazione di tre differenti modelli di comportamento dei consumatori in presenza di errori di misura.
L'identificazione risulta particolarmente difficile a causa della elevata non-linearità delle specificazioni utilizzate e di alcune peculiarità proprie dei modelli con dati di consumo. In molti casi infatti, la presenza di covariate misurate con errore implica errori di misura correlati nella variabile dipendente. Questo complica ulteriormente l'identificazione del modello, invalidando la maggior parte dei risultati presenti nella letteratura su errori di misura in modelli non-lineari.
Il contenuto della tesi è discusso in tre Capitoli. Il primo Capitolo discute l'identificazione di una particolare specificazione di curve di Engel quando la spesa totale non osservata è endogena e misurata con errore. Il secondo Capitolo studia l'identificazione di un modello non-lineare molto generale con errori di misura correlati su entrambi i lati dell'equazione. Il terzo Capitolo ottiene identificazione e stima della distribuzione di consumo quando solo la spesa e il numero di acquisti sono osservati
Identication and Estimation of Engel Curves with Endogenous and Unobserved Expenditures
Get PDFWhen dealing with the estimation of Engel curves, measurement errors in expenditure data and simultaneity are likely sources of endogeneity. In this paper we study identication of the parameters that characterize an Engel curve in the presence of both. We consider specications where budget shares are polynomials in the logarithm of total expenditure, which is the case frequently encountered in empirical applications. We propose an estimation procedure which is an extension of that in Lewbel (1996), and exploits a control function assumption to correct for the endogeneity of the true unobserved total expenditure
Misreported Schooling, Multiple Measures and Returns to Educational Qualifications
No full textAbstractWe consider the identification and estimation of the average wage return to attaining educational qualifications when attainment is potentially measured with error. By exploiting two independent measures of qualifications, we identify the extent of misclassification in administrative and self-reported data on educational attainment. The availability of multiple self-reported educational measures additionally allows us to identify the temporal patterns of individual misreporting errors across survey waves. We provide the first reliable estimate of a highly policy relevant parameter for the UK, namely the return from attaining any academic qualification compared to leaving school at the minimum age without any formal qualification. We identify returns to qualifications under two alternative settings: a strong ignorability assumption and an exclusion restriction. All these results are obtained by casting the identification problem in terms of a mixture model, and using a semi-parametric estimation approach based on balancing scores, which allows for arbitrarily heterogeneous individual returns
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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