The Role of model uncertainty and learning in the U.S. postwar policy response to oil prices

This paper studies optimal monetary policy in a framework that explicitly accounts for policymakers' uncertainty about the channels of transmission of oil prices into the economy. More specfically, I examine the robust response to the real price of oil that US monetary authorities would have been recommended to implement in the period 1970 2009; had they used the approach proposed by Cogley and Sargent (2005b) to incorporate model uncertainty and learning into policy decisions. In this context, I investigate the extent to which regulator' changing beliefs over different models of the economy play a role in the policy selection process. The main conclusion of this work is that, in the specific environment under analysis, one of the underlying models dominates the optimal interest rate response to oil prices. This result persists even when alternative assumptions on the model's priors change the pattern of the relative posterior probabilities, and can thus be attributed to the presence of model uncertainty itself.

Decision-theoretic analysis of forensic sampling criteria using Bayesian decision networks

Sampling issues represent a topic of ongoing interest to the forensic science community essentially because of their crucial role in laboratory planning and working protocols. For this purpose, forensic literature described thorough (Bayesian) probabilistic sampling approaches. These are now widely implemented in practice. They allow, for instance, to obtain probability statements that parameters of interest (e.g., the proportion of a seizure of items that present particular features, such as an illegal substance) satisfy particular criteria (e.g., a threshold or an otherwise limiting value). Currently, there are many approaches that allow one to derive probability statements relating to a population proportion, but questions on how a forensic decision maker - typically a client of a forensic examination or a scientist acting on behalf of a client - ought actually to decide about a proportion or a sample size, remained largely unexplored to date. The research presented here intends to address methodology from decision theory that may help to cope usefully with the wide range of sampling issues typically encountered in forensic science applications. The procedures explored in this paper enable scientists to address a variety of concepts such as the (net) value of sample information, the (expected) value of sample information or the (expected) decision loss. All of these aspects directly relate to questions that are regularly encountered in casework. Besides probability theory and Bayesian inference, the proposed approach requires some additional elements from decision theory that may increase the efforts needed for practical implementation. In view of this challenge, the present paper will emphasise the merits of graphical modelling concepts, such as decision trees and Bayesian decision networks. These can support forensic scientists in applying the methodology in practice. How this may be achieved is illustrated with several examples. The graphical devices invoked here also serve the purpose of supporting the discussion of the similarities, differences and complementary aspects of existing Bayesian probabilistic sampling criteria and the decision-theoretic approach proposed throughout this paper.

Bayesian classification criterion for forensic multivariate data

This study presents a classification criteria for two-class Cannabis seedlings. As the cultivation of drug type cannabis is forbidden in Switzerland, law enforcement authorities regularly ask laboratories to determine cannabis plant's chemotype from seized material in order to ascertain that the plantation is legal or not. In this study, the classification analysis is based on data obtained from the relative proportion of three major leaf compounds measured by gas-chromatography interfaced with mass spectrometry (GC-MS). The aim is to discriminate between drug type (illegal) and fiber type (legal) cannabis at an early stage of the growth. A Bayesian procedure is proposed: a Bayes factor is computed and classification is performed on the basis of the decision maker specifications (i.e. prior probability distributions on cannabis type and consequences of classification measured by losses). Classification rates are computed with two statistical models and results are compared. Sensitivity analysis is then performed to analyze the robustness of classification criteria.

Detection of nandrolone metabolites in urine after a football game in professional and amateur players: a Bayesian comparison.

Nandrolone (19-nortestosterone) is a widely used anabolic steroid in sports where strength plays an essential role. Once nandrolone has been metabolised, two major metabolites are excreted in urine, 19-norandrosterone (NA) and 19-noretiocholanolone (NE). In 1997, in France, quite a few sportsmen had concentrations of 19-norandrosterone very close to the IOC cut off limit (2ng/ml). At that time, a debate took place about the capability of the human male body to produce by itself these metabolites without any intake of nandrolone or related compounds. The International Football Federation (FIFA) was very concerned with this problematic, especially because the World Cup was about to start in France. In this respect, a statistical study was held with all football players from the first and second divisions of the Swiss Football National League. All players gave a urine sample after effort and around 6% of them showed traces of 19-norandrosterone. These results were compared with amateur football players (control group) and around 6% of them had very small amounts of 19-norandrosterone and/or 19-noretiocholanolone in urine after effort, whereas none of them had detectable traces of one or the other metabolite before effort. The origin of these compounds in urine after a strenuous physical activity is still unknown, but three hypotheses can be put forward. First, an endogenous production of nandrolone metabolites takes place. Second, nandrolone metabolites are released from the fatty tissues after an intake of nandrolone, some related compounds or some contaminated nutritive supplements. Finally, the sportsmen may have taken something during or just before the football game.

Cooperative learning: learning to cooperate, cooperating to learn

This research project is an attempt to give arguments in favour of using cooperative learning activities in FL classrooms as an effective approach to learning. The arguments offered are presented from two different perspectives: the first one is based on the empirical study of three students working together to achieve a common goal. The second one is a compilation of the trainee teacher's experiences during her practicum periods in a high school regarding group work. This part is illustrated by some examples that emphasize that cooperative learning can facilitate learning, promote socialisation and increase students' self-esteem

The learning process as a cooperative task among teachers and students

This research project gathers several ideas and guidelines on professional improvement as a teacher. This study includes two empirical studies. The first one focuses mainly on the teacher's figure. It is meant to be a study of the several resources that the teacher uses in order to construct the student's knowledge in an English classroom context. The second empirical study focuses on the students. It is a study on how students learn cooperatively by analyzing their oral productions when working in small groups

How to avoid gender bias in classroom interaction? A cooperative learning experience

This project aims to analyse the kind of questions the teacher asks students in order to encourage them to participate in her classes. Consequently, the researcher has read relevant literature and has analysed a short excerpt of a video recorded during her first practicum. She has also analysed a number of activities carried out during her second practicum in order to find out if she had improved her questioning skills in the classroom

La implementació dels ECTS a la titulació de Formació del Professorat : fomentant l'aprenentatge significatiu mitjançant b-learning, metodologies didàctiques innovadores i l'avaluació contínua

Aquest projecte ha servit per (1) establir un treball col·laboratiu entre el professorat que habitualment impartim les assignatures de Didàctica general i atenció a la diversitat i Organització del Centre Escolar; (2) dissenyar conjuntament espais del campus virtual en la plataforma moodle; (3) compartir material i experiències docents fent formació entre iguals; (4) dissenyar i desenvolupar accions didàctiques innovadores per afavorir l'aprenentatge significatiu; (5) prendre posició respecte a l'elaboració dels nous graus de Formació del Professorat i reelaborar els plans docents nous. Les noves titulacions, el disseny per competències, l’EEES ens ha obligat a fer una reflexió sobre la nostra docència, l’educació superior i la formació dels futurs mestres. Aquest projecte ha recolzat la tasca habitual, donant-li una orientació concreta, en ell hem estat implicat un grup important de professors i professores així com d’alumnes perquè s’ha implementat en els 13 grups d’alumnes de Formació del Professorat i en dues assignatures troncals i obligatòries. Per fer seguiment del treball hem analitzat els productes d’aprenentatges, els espais moodle, així mateix hem anat recollint les valoracions dels estudiants fent qüestionaris i grups de discussió. Tot i que el treball desenvolupat es considera positiu, hi ha aspectes per millorar que també es destaquen en l’informe: dificultats per manca de temps, poc reconeixement, necessitat de cohesionar i estabilitzar equips docents, necessitat d’incorporar tècniques especialistes en el disseny d’entorns virtuals d’aprenentatge en els equips docents, entre d’altres. D’altra banda amb l’elaboració dels nous plans d’estudis les assignatures amb les que hem treballat han perdut l’entitat i el pes que tenien per tenir-ne una altra i en des de 2007 fins a ara hem anat perdent professorat estable i incorporant associats. Fets que fan necessari seguir avançant d’altres maneres, per tant finalitzem un projecte, però es necessari replantejar-se un altre.

Cooperative learning in the ESL classroom

This research explores the advantages and disadvantages of collaborative learning departing from two different methodological studies. In the first one, we will go deep into the reflections about group work of a student-teacher in her first experiences during a two months practicum in Sabadell's Emily Bronte. In the second one, we will analyze in a more empirical way the interaction that takes place among a trio of students engaged in a question-answering task about a text based on a three minutes vignette recorded on January 2010

Public and private learning from prices, strategic substitutability and complementarity, and equilibrium multiplicity

We study a general static noisy rational expectations model where investors have private information about asset payoffs, with common and private components, and about their own exposure to an aggregate risk factor, and derive conditions for existence and uniqueness (or multiplicity) of equilibria. We find that a main driver of the characterization of equilibria is whether the actions of investors are strategic substitutes or complements. This latter property in turn is driven by the strength of a private learning channel from prices, arising from the multidimensional sources of asymmetric information, in relation to the usual public learning channel. When the private learning channel is strong (weak) in relation to the public we have strong (weak) strategic complementarity in actions and potentially multiple (unique) equilibria. The results enable a precise characterization of whether information acquisition decisions are strategic substitutes or complements. We find that the strategic substitutability in information acquisition result obtained in Grossman and Stiglitz (1980) is robust. JEL Classification: D82, D83, G14 Keywords: Rational expectations equilibrium, asymmetric information, risk exposure, hedging, supply information, information acquisition.