Forecasting Inflation Through a Bottom-Up Approach: The Portuguese Case

The aim of this paper is to assess inflation forecasting acurracy over the short-term horizon using Consumer Price Index (CPI) disaggregated data. That is, aggregating forecasts is compared with aggregate forecasting. In particular, three questions are addressed: i) one should bottom-up or not, ii) how bottom one should go and iii) how one should model at the bottom. In contrast with the literature, di erent levels of data dis-aggregation are allowed, namely a higher disaggregation level than the one considered up to now. Moreover, both univariate and multivariate models are considered, such as SARIMA and SARIMAX models with dynamic common factors. An out-of-sample forecast comparison (up to twelve months ahead) is done using Portuguese CPI dataset. Aggregating the forecasts seems to be better than aggregate forecasting up to a five-months ahead horizon. Moreover, this improvement increases with the disaggregation level and the multivariate modelling outperforms the univariate one in the very short-run.

Back to basics: Data revisions

With few exceptions, most economic data undergo revisions. Although frequently neglected, data revisions may have implications, not only for economic analysis, but also for policy decisions, as revisions may alter current assessment and forecasts of economic developments. In this paper, we reassess data revisions analysis and its impact on forecasting, presenting an encompassing and unified perspective on this subject. For this purpose, we built a real-time database for Portuguese exports and imports of goods. We present a broad set of the measures typically used to gauge revisions and add to this discussion by clarifying the relations between revisions to deferent types of series (for example, revisions to month-on-month and year-on-year rates of change). Furthermore, regarding the (un)predictability of revisions, we suggest an alternative testing approach. The key feature of this approach is that it takes into account both in-sample and out-of-sample performances. We also discuss the impact of revisions on forecasting, focusing on short-term forecasting of first releases. Even though not accounting for data revision implications can lead to suboptimal results, our findings reinforce the need for a case by case analysis.

Inflation (mis)perceptions in the euro area

There has been a growing interest on inflation perceptions in the euro area, in particular, following the euro cash changeover. It has been pointed out that a gap emerged between observed and perceived inflation since the introduction of the euro notes and coins. Such a statement relies on the fact that inflation perceptions, measured by the well-known balance statistic from the European Commission's consumer survey, hiked after January 2002 and remained high thereafter, as opposed to the observed inflation, which has remained fairly stable. In this paper, we discuss the issue of inflation perceptions measurement, by comparing the balance statistic with an alternative refined measure, which is computed using the probability method. We argue that the balance statistic should be used carefully, as it can induce to misleading conclusions. In fact, we provide, for both euro area and country level, evidence showing that, using the proposed alternative measure, the breakdown in the relationship between observed and perceived inflation did not occur at the time of the euro cash changeover.

Reverberations of Wittgenstein’s philosophy on mathematical education

The present text aims at elucidating the possible contributions resulting from Wittgenstein’s philosophy, in its second phase, so as to allow us to consider some of the propositions presented to Mathematics Education. First of all, we shall start by emphasizing the importance of the conceptions of rationality and language developed by the Austrian philosopher in the sense of our questioning of the academic mathematic claim for universality, then, on a further moment, we move on to analyze one of its implications for School Mathematics Education. In a specific way, on the second part of the text, making use of the theoretical tools provided by the work of the second Wittgenstein, we problematize the deep-rooted truth spread in the educational discourse which states the need to take into account and starting point, the student’s reality in the classroom as a way to attribute meaning to school mathematics. We claim here that such enterprise is impossible, by arguing that the language games of school mathematics and those which constitute the social practices, in spite of having family similarities among them, are, in fact, different, and the “passage” from a language game, pertaining to a certain form of life, into another, would not guarantee the permanence of meaning. Rather, it suggests its transformation.O presente texto busca evidenciar as possíveis contribuições advindas da filosofia wittgensteiniana, em sua segunda fase, para pensarmos sobre algumas proposições que têm sido colocadas à Educação Matemática. Começamos destacando a importância das concepções de racionalidade e de linguagem desenvolvidas pelo filósofo austríaco no sentido de interrogarmos sobre a pretensão de universalidade da matemática acadêmica para, em um momento posterior, analisarmos uma das implicações para a Educação Matemática Escolar. De forma específica, na segunda parte do texto, servindo-nos de ferramentas teóricas oriundas da obra do segundo Wittgenstein, problematizamos a verdade que se propagou e se enraizou no discurso educacional ao afirmar a necessidade de se trabalhar a partir da realidade do aluno em sala de aula a fim de se atribuir significado à matemática escolar. Sustentamos aqui a impossibilidade de tal empreendimento, argumentando que os jogos de linguagem da matemática escolar e aqueles que constituem as práticas sociais, apesar de guardarem semelhanças de família entre si, são distintos e a “passagem” de um jogo de linguagem pertencente a uma forma de vida para a outra não garantiria a permanência do significado. Antes sugere sua transformação

Inflation expectations in the euro area: Are consumers rational?

In this paper, we propose a quantitative measure for inflation expectations based on consumer survey data. Thereafter, we proceed to testing the rationality assumption. This issue is of noteworthy interest in its own as it is commonly assumed in the theoretical modelling literature that the rational expectations hypothesis holds. This analysis is conducted for the euro area as a whole, as well as for several member countries, using a sample covering the last two decades. Moreover, we also assess if the conclusions hold when one focuses on the post-euro introduction period.

Vacinas e plantas, relação em larga escala

As vacinas atualmente são consideradas imprescindíveis para o início do desenvolvimento do ser humano, sendo responsáveis pela proteção contra várias doenças infeciosas. Surgiram no século XIX com a produção da vacina contra a varíola. Vírus como a raiva, poliomielite, influenza e hepatite B foram combatidos com o desenvolvimento de vacinas ao longo dos séculos e, até aos dias de hoje ainda estão em comercialização. Este tipo de preparações é eficaz, conferindo proteção em alguns casos para toda a vida, ou por um determinado período de tempo. Fatores económicos e falhas no sistema de produção de proteínas terapêuticas levaram a investigar outros tipos de biofábricas. Os organismos fotossintéticos são os que apresentam mais vantagens, são económicos, crescem facilmente e permitem um melhor controlo de contaminações. As plantas podem expressar os antigénios ou anticorpos por dois sistemas o estável e o transitório, sendo o último o mais utilizado na produção de vacinas. O conceito de Plant Molecular Pharming é a mais recente tecnologia, existindo fábricas especializadas em produzir produtos terapêuticos baseados em plantas. A vacina contra o vírus Influenza e contra o Ébola são dois exemplos que estão bem encaminhados para atingir o sucesso.Vaccines are currently considered essential for the beginning of human development, being responsible for the protection against various infectious diseases. They emerged in the nineteen century with the production of the vaccine against smallpox. Viruses such as rabie, polio, influenza and hepatitis B have been combated with the development of vaccines over the centuries and to the present day are still in commercialization. This type of preparations is effective, conferring protection in some cases for life, or for a certain period of time. Economic factors and failure in therapeutic proteins production systems have led to investigate other types of biofactories. The photosynthetic organisms are those which have further advantages, are economical, grow easily and allow better control of contamination. The plants can express the antigens or antibodies of two systems satble and transient, but the most used in production of vaccine is the transient system. The concept of Plant Molecular Pharming is the new technology, existing factories specialized in producing therapeutic products based on plants. The vaccines against the influenza virus and Ebola are two examples that are on track to achieve success