1,721,051 research outputs found
Innovation and productivity of Dutch firms: A panel data analysis
No full textThis paper uses an extended version of the well-established Crépon, Duguet and Mairesse model (1998, CDM hereafter) to model empirically the innovation-productivity relationship using data on patent applications by Dutch firms to the European Patent Office.
We use an extended version of the well-established Crepon, Duguet and Mairesse model (1998, CDM hereafter) to model empirically the innovation-productivity relationship using data for the 2000-2006 period on patent applications by Dutch firms to the European Patent Office. The CDM model disentangles the impact of R&D expenditures on patents and the impact of patents on productivity. A multiple-equation dynamic panel data model of R&D, patent applications or citations and multi-factor productivity (MFP) growth is estimated that suits multiple data distribution properties. We explicitly take into account the role of dynamics and firm-level unobserved heterogeneity in each of the innovation processes and productivity. We find evidence that the output innovation affects productivity positively, which seems to be robust across specifications. We also find that the strong presence of random effects for individual heterogeneity in explaining the R&D patents relationship is an important driver to innovation. While the estimates of R&D and dynamics depend on whether these unobserved characteristics are taken into account, we find robust evidence on the role of firm size in explaining patent and citation counts.We gratefully acknowledge support from the Netherlands Organization for Scientific Research (NWO) under their research program “Dynamism of Innovation” and the Research Foundation of Flanders (FWO) for a travel grant
Innovation and productivity of Dutch firms: A panel data analysis
No full textThis paper uses an extended version of the well-established Crépon, Duguet and Mairesse model (1998, CDM hereafter) to model empirically the innovation-productivity relationship using data on patent applications by Dutch firms to the European Patent Office.
We use an extended version of the well-established Crepon, Duguet and Mairesse model (1998, CDM hereafter) to model empirically the innovation-productivity relationship using data for the 2000-2006 period on patent applications by Dutch firms to the European Patent Office. The CDM model disentangles the impact of R&D expenditures on patents and the impact of patents on productivity. A multiple-equation dynamic panel data model of R&D, patent applications or citations and multi-factor productivity (MFP) growth is estimated that suits multiple data distribution properties. We explicitly take into account the role of dynamics and firm-level unobserved heterogeneity in each of the innovation processes and productivity. We find evidence that the output innovation affects productivity positively, which seems to be robust across specifications. We also find that the strong presence of random effects for individual heterogeneity in explaining the R&D patents relationship is an important driver to innovation. While the estimates of R&D and dynamics depend on whether these unobserved characteristics are taken into account, we find robust evidence on the role of firm size in explaining patent and citation counts.We gratefully acknowledge support from the Netherlands Organization for Scientific Research (NWO) under their research program “Dynamism of Innovation” and the Research Foundation of Flanders (FWO) for a travel grant
Global Warming and Local Dimming: The Statistical Evidence
Full text linkTwo effects largely determine global warming: the well-known greenhouse effect and the less well-known solar radiation effect. An increase in concentrations of carbon dioxide and other greenhouse gases contributes to global warming: the greenhouse effect. In addition, small particles, called aerosols, reflect and absorb sunlight in the atmosphere. More pollution causes an increase in aerosols, so that less sunlight reaches the Earth (global dimming). Despite its name, global dimming is primarily a local (or regional) effect. Because of the dimming the Earth becomes cooler: the solar radiation effect. Global warming thus consists of two components: the (global) greenhouse effect and the (local) solar radiation effect, which work in opposite directions. Only the sum of the greenhouse effect and the solar radiation effect is observed, not the two effects separately. Our purpose is to identify the two effects. This is important, because the existence of the solar radiation effect obscures the magnitude of the greenhouse effect. We propose a simple climate model with a small number of parameters. We gather data from a large number of weather stations around the world for the period 1959–2002. We then estimate the parameters using dynamic panel data methods, and quantify the parameter uncertainty. Next, we decompose the estimated temperature change of 0.73ºC (averaged over the weather stations) into a greenhouse effect of 1.87ºC, a solar radiation effect of −1.09ºC, and a small remainder term. Finally, we subject our findings to extensive sensitivity analyses
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Estimating the joint survival probabilities of married individuals
No full textWe estimate the joint survival probability of spouses using a large random sample drawn from a Dutch census. As benchmarks we use two bivariate Weibull models. We consider more flexible models, using a semi-nonparametric approach, by extending the independent Weibull distribution using squared polynomials. Also based on a nonparametric comparison, we find that extending the independent Weibull distribution by a squared third order polynomial shows the best performance. We illustrate our model by calculating remaining life expectancies and annuity values. We find that the husbands life expectancy at birth is generally increasing with his wifes age of death and the wifes life expectancy at birth is generally increasing with her husbands age of death. Ignoring the dependence between the remaining lifetimes of spouses may lead to an underestimation of the value of a joint annuity and an overestimation of the value of a single-life annuity, but less than suggested on the basis of the previous literature
Variations on the Author
Full text link“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
Full text linkWe 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
Full text linkWe 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
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