There should not be any mystery: a comment on sampling issues in bibliometrics

A research unit wants to assess whether its publications tend to be more cited than academic publications in general. This research unit could be anything from a lonesome researcher to a national research council sponsoring thousands of researchers. The unit has access to the (inverted) percentile ranks of n of its publications: each publication has an associated real number between 0 and 100, which measures the percentage of publications in its reference set that receive at least as many citations as its own citation count. For instance, if the percentile rank of one publication is 10%, it means that 90% of publications in its reference set are less cited and 10% are cited at least as much. Now, say that the unit takes the mean of its n percentile ranks and reaches a value below 50%. Can the unit confidently conclude that it produces research that tends to be more cited than most publications? The article by Richard Williams and Lutz Bornmann (in press) proposes to answer this kind of question by relying on standard statistical procedures of significance testing and power analysis. I am deeply sympathetic to this proposal. I find, however, their exposition to be sometimes clouded in mystery. I suspect that many readers will therefore be unconvinced by their proposal. In this comment, I endeavor to make a clearer case for their general strategy. It should not be mysterious why this strategy is sound. By clarifying the case, I show that some technical decisions of Williams and Bornmann are mistakes (choosing a two-tailed instead of a one-tailed test), lead to less efficient estimates (choosing the t-statistic instead of simply relying on the mean) or are not as prudent as they should be (presuming a particular standard deviation). Before making these technical points, I start with a more conceptual issue: in the next section, I dispel some confusion regarding the notion of randomness in the presentation of the authors

Macrodynamics of economics: a bibliometric history

A history of specialties in economics since the late 1950s is constructed on the basis of a large corpus of documents from economics journals. The production of this history relies on a combination of algorithmic methods that avoid subjective assessments of the boundaries of specialties: bibliographic coupling, automated community detection in dynamic networks and text mining. these methods uncover a structuring of economics around recognizable specialties with some significant changes over the time-period covered (1956-2014). Among our results, especially noteworthy are (a) the clearcut existence of 10 families of specialties, (b) the disappearance in the late 1970s of a specialty focused on general economic theory, (c) the dispersal of the econometrics-centered specialty in the early 1990s and the ensuing importance of specific econometric methods for the identity of many specialties since the 1990s, (d) the low level of specialization of individual economists throughout the period in contrast to physicists as early as the late 1960s

Technical appendix to Macrodynamics of economics: a bibliometric history

A history of specialties in economics since the late 1950s is constructed on the basis of a large corpus of documents from economics journals. The production of this history relies on a combination of algorithmic methods that avoid subjective assessments of the boundaries of specialties: bibliographic coupling, automated community detection in dynamic networks, and text mining. These methods uncover a structuring of economics around recognizable specialties with some significant changes over the period covered (1956–2014). Among our results, especially noteworthy are (1) the clear-cut existence of ten families of specialties, (2) the disappearance in the late 1970s of a specialty focused on general economic theory, (3) the dispersal of the econometrics-centered specialty in the early 1990s and the ensuing importance of specific econometric methods for the identity of many specialties since the 1990s, and (4) the low level of specialization of individual economists throughout the period in contrast to physicists as early as the late 1960s

The Variety-of-Evidence Thesis : A Bayesian Exploration of its Surprising Failures

Diversity of evidence is widely claimed to be crucial for evidence amalgamation to have distinctive epistemic merits. Bayesian epistemologists capture this idea in the variety-of-evidence thesis: ceteris paribus, the strength of confirmation of a hypothesis by an evidential set increases with the diversity of the evidential elements in that set. Yet, formal exploration of this thesis has shown that it fails to be generally true. This article demonstrates that the thesis fails in even more circumstances than recent results would lead us to expect. Most importantly, it can fail whatever the chance that the evidential sources are unreliable. Our results hold for two types of degrees of variety: reliability independence and testable aspect independence. We conclude that the variety-of-evidence thesis can, at best, be interpreted as an exception-prone rule of thumb

Experts et valeurs : usages (il)légitimes?

Pour les opposants à l’installation de compteurs dits «intelligents» par les firmes de distribution d’électricité, les discours rassurants des experts à propos des effets des ondes électromagnétiques sur la santé ne sont pas crédibles. Ces experts seraient, selon eux,«vendus» aux compagnies tirant profit de cette technologie avec qui ils partagent des intérêts et, peut-être surtout, des valeurs et des représentations communes. Influencés par des valeurs commerciales, ils offriraient une représentation biaisée des risques technologiques. Cette forme de critique est très répandue dans les débats sociotechniques: on remet en doute l’opinion experte majoritaire, car elle serait infectée par des valeurs qui l’éloignent des faits. Ce doute se fonde parfois sur une pure théorie du complot: selon certains interprètes du Climategate, les scientifiques experts du climat auraient trafiqué les données de façon concertée, puisque leur carrière se fonde sur la croyance que les changements climatiques sont bien réels. Dans d’autres cas, les mécanismes invoqués ne relèvent pas de l’action concertée: on entend souvent que les économistes auraient tendance à accepter des hypothèses sur l’inefficacité d’un bon nombre d’interventions étatiques sur la base de convictions morales à tendance libertarienne

Operating data of a specific Aquatic Center as a Benchmark for dynamic model learning: search for a valid prediction model over an 8-hour horizon

This article presents an identification benchmark based on data from a public swimming pool in operation. Such a system is both a complex process and easily understandable by all with regard to the stakes. Ultimately, the objective is to reduce the energy bill while maintaining the level of quality of service. This objective is general in scope and is not limited to public swimming pools. This can be done effectively through what is known as economic predictive control. This type of advanced control is based on a process model. It is the aim of this article and the considered benchmark to show that such a dynamic model can be obtained from operating data. For this, operational data is formatted and shared, and model quality indicators are proposed. On this basis, the first identification results illustrate the results obtained by a linear multivariable model on the one hand, and by a neural dynamic model on the other hand. The benchmark calls for other proposals and results from control and data scientists for comparison

Practical Considerations when Using the Swedish Fall Cone

This paper presents the results of Swedish fall cone tests and Casagrande liquid limit tests conducted on saline Champlain Sea clay samples from Lachenaie, Quebec. The main objective was to study a few hitherto unanswered practical questions regarding these testing methods. Penetration range is found to affect the Hansbo’s relationship used in fall cone experiments, while the mass and the bluntness degree of the cone have no effect on it. A direct relationship between thixotropic regain in shear strength and sensitivity is found. When measuring the liquid limit, if only the first penetration depth is recorded, results are up to 5% smaller than those obtained when following the standard procedure of CAN/BNQ-2501-092. With this standard, the average of the first two penetration depths within 0.3 mm of each other is recorded. These penetrations usually follow the bulk of the thixotropic shear strength regain. The Swedish fall cone was compared to the traditional Casagrande apparatus for liquid limit determinations. The two methods yielded identical results in the studied conditions (saline Lachenaie clay with liquid limit between 44% and 75%). An incorrect calibration of the height-of-drop of 1.4 mm led to a mean error of 6 liquid limit points. This error is greater than the theoretical error obtained by assuming that the number of blows is proportional to the square of the height-of-drop

Des produits issus d’animaux terrestres recevant une alimentation enrichie en DHA algal peuvent contribuer à la couverture des besoins en cet acide gras essentiel

Ce travail présente une méthode permettant d’augmenter la consommation en DHA de la population sans accroitre le prélèvement halieutique, grâce à la production de produits provenant d’animaux terrestres nourris avec des aliments contenant du DHA provenant de microalgues de culture et d’ALA provenant du lin extrudé. Après une identification des espèces fixant le DHA en quantité importante (pondeuse, lapins, poulet de chair), des essais réalisés sur ces animaux (21 sur pondeuses, 9 sur lapins, 6 sur poulets de chair) ont permis de déterminer les conditions d’enrichissement en DHA ainsi que les teneurs en cet acide gras que l’on peut atteindre dans ces produits. Ainsi, avec cette alimentation, le contenu en DHA des œufs est de 200 mg / 100 grammes soit 3,5 fois plus qu’un œuf standard; pour le lapin (par exemple, la gigolette), cette valeur est également de 200 mg / 100 grammes soit 10 fois plus qu’une viande de lapin standard; et pour le poulet de chair (par exemple, le blanc) 83 mg / 100 grammes soit 4 fois plus qu’une viande de poulet de chair standard. La plupart de ces produits peuvent alléguer « Riche en oméga 3 » ou « Source d’oméga 3 ». Ces différents aliments peuvent être associés dans des menus permettant d’atteindre les recommandations d’ingestion de DHA sans augmenter la consommation de poisson, améliorant ainsi la santé de la population et celle de la planète dans le respect des habitudes alimentaires.

Central banking and inequalities: taking off the blinders

What is the relation between monetary policy and inequalities in income and wealth? This question has received insufficient attention, especially in light of the unconventional policies introduced since the 2008 financial crisis. The article analyzes three ways in which the concern central banks show for inequalities in their official statements remains incomplete and underdeveloped. First, central banks tend to care about inequality for instrumental reasons only. When they do assign intrinsic value to containing inequalities, they shy away from trade-offs with the standard objectives of monetary policy that such a position entails. Second, central banks play down the causal impact monetary policy has on inequalities. When they do acknowledge it, they defend their actions by claiming that it is an unintended side effect, that it is temporary, and/or that any alternative policy would fare even worse. The article appeals to the doctrine of double effect to criticize these arguments. Third, even if one accepts that inequalities should be contained and that today’s monetary policies exacerbate them, is it both desirable and feasible to make containing inequalities part of the mandate of central banks? The article analyzes and rejects three attempts on the part of central banks to answer this question negatively