Using social connection information to improve opinion mining: Identifying negative sentiment about HPV vaccines on Twitter

The manner in which people preferentially interact with others like themselves suggests that information about social connections may be useful in the surveillance of opinions for public health purposes. We examined if social connection information from tweets about human papillomavirus (HPV) vaccines could be used to train classifiers that identify antivaccine opinions. From 42,533 tweets posted between October 2013 and March 2014, 2,098 were sampled at random and two investigators independently identified anti-vaccine opinions. Machine learning methods were used to train classifiers using the first three months of data, including content (8,261 text fragments) and social connections (10,758 relationships). Connection-based classifiers performed similarly to content-based classifiers on the first three months of training data, and performed more consistently than content-based classifiers on test data from the subsequent three months. The most accurate classifier achieved an accuracy of 88.6% on the test data set, and used only social connection features. Information about how people are connected, rather than what they write, may be useful for improving public health surveillance methods on Twitter

Optimal origin-based commodity taxation in a small open economy

This paper investigates whether the pursuit of redistributional objectives may provide a rationale for origin-based taxation in small open economies. The analysis is developed in a simple two-class economy where consumers are classified according to the type of labour they supply. As world prices are given for a small open economy, the full burden of origin-based commodity taxes falls on the two types of labour. When a non-linear tax is levied on labour income, origin-based taxes cannot directly improve income distribution as the two types of labour face different marginal tax rates. However, the government can exploit the differential incidence of these origin-based taxes and increase social welfare by relaxing the self-selection constraints that bind the non-linear tax. Rather surprisingly, the value judgements embedded in the social welfare functional do not affect the structure of optimal origin-based commodity taxation. The paper also shows that the optimal structure of origin-based commodity taxation does not change when the labour income tax schedule is constrained to be linear, and that a positive source-based tax on capital income may be optimal if it results in a differential burden on the two types of labour

Plusvalenze e imposta societaria: spunti per una riforma dell'Ires

Il trattamento fiscale delle plusvalenze nell'ambito dell'imposta sulle societ

Meccanismi di correzione della tassazione delle plusvalenze alla realizzazione

Capital gains taxation on a realization basis is known to give rise to a number of distortions and to several arbitrage opportunities that can result in a significant erosion in the tax base. Most countries tackle these problems through a series of "ad hoc" adjustments to "pure" realization based taxation, such as separate treatment of ordinary income and capital gains, reduced tax rates on long-term capital gains, limited loss offsets. The theoretical literature proposes several methods which may provide a more comprehensive solution along the lines suggested by Vickrey (1939) and Meade (1978). However no country, except Italy, have experimented any of these methods. This paper reviews the alternatives in order to evaluate them primarily on the basis of compliance and administrative costs and political feasibility. The analysis highlights that most of the difficulties in the implementation of any of the comprehensive solutions are related to the taxation of intermediate payments such as dividends. This issue has been relatively neglected by the existing literature. We show that no proposal may overcome all the objections raised in the literature and in the debate on the Italian experiment. Each method should be judged as a second best solution and evaluated with reference to a specific institutional and economic environment

Plusvalenze e imposta societaria: spunti per una riforma dell'Ires

Il trattamento fiscale delle plusvalenze nell'ambito dell'imposta sulle societ

Tassare i redditi o i consumi?

Diverse ragioni sono state avanzate a favore di uno spostamento dell'imposizione dal reddito al consumo, e in particolare verso l'Iva: la possibilità di ridurre il cuneo fiscale sul lavoro, di rendere più competitivi i beni esportati, di aumentare l'equità in presenza di evasione fiscale. Non tutti questi argomenti reggono ad un'analisi più approfondita, e gli effetti regressivi potrebbero essere rilevanti