Reasoning under uncertainty and multi-criteria decision making in data privacy

By means of an integration of decision theory and probabilistic models, we explore and develop methods for improving data privacy. Our work encompasses disclosure control tools in statistical databases and privacy requirements prioritization; in particular we propose a Bayesian approach for the on-line auditing in Statistical Databases and Pairwise Comparison Matrices for privacy requirements prioritization. The first approach is illustrated by means of examples in the context of statistical analysis on the census and medical data, where no salary (resp. no medical information), that could be related to a specific employee (resp. patient), must be released; the second approach is illustrated by means of examples, such as an e-voting system and an e-banking service that have to satisfy privacy requirements in addition to functional and security ones. Several fields in the social sciences, economics and engineering will benefit from the advances in this research area: e-voting, e-government, e-commerce, e-banking, e-health, cloud computing and risk management are a few examples of applications for the findings of this research.     

The impossibility of compromise: some uniqueness properties of expected utility preferences

Summary. We focus on the following uniqueness property of expected utility preferences: Agreement of two preferences on one interior indifference class implies their equality. We show that, besides expected utility preferences under (objective) risk, this uniqueness property holds for subjective expected utility preferences in Anscombe-Aumann's (partially subjective) and Savage's (fully subjective) settings, while it does not hold for subjective expected utility preferences in settings without rich state spaces. Indeed, when it holds the uniqueness property is even stronger than described above, as it needs only agreement on binary acts. The extension of the uniqueness property to the subjective case is possible because beliefs in the mentioned settings are shown to satisfy an analogous property: If two decision makers agree on a likelihood indifference class, they must have identical beliefs. Received: November 15, 1999; revised version: December 29, 1999     

Exchange rate and interest rate polarization

Exchange Rate and Interest Rate Polarization. - The relationship between the polarization phenomenon in foreign exhange markets and a similar regu-larity in interest rate differentials is considered. In the case of perfect substitutability and of perfect foresight, both polarizations would be perfectly complementary. Risk premia and forecast errors, however, might induce some degree of substitutability between the two concepts. Throughout almost the entire EMS experience, in France and Italy both phenomena appear to be equivalent. At the end of the 80s, however, interest rate polarization has surged at the expense of exchange rate polarization. In fact, a bias in estimates was found to explain this recent behaviour.     

Asymmetric competition and collection rates differentials: determinants of prices in international telephone service markets

The paper investigates determinants of pricing in international telephone service markets. The analysis—focused on 24 worldwide national markets—shows the impact of several telecommunications-specific and macroeconomic variables on collection rate differentials and traffic imbalance between countries. An econometric model is aimed at performing quantitative analysis and providing support to future telecommunications policies.     

Asymmetry in mobile access charges: is it an effective regulatory measure?

This paper analyses the regulation of the market of voice call termination on mobile networks, by considering the remedy of asymmetric access charges and the hypothesis of discriminatory retail pricing. In the two way interconnection, the operators revenue depends on two factors: the retail price and the access charge. If the retail prices are different between calls that terminate on the same network (on-net) and calls that terminate on the rival network (off-net), the competition is more complex, involving positive networks externalities for the incumbent operator. In order to reduce the competitive disadvantage for new entrants and smaller operators many European regulation authorities have introduced the remedy of asymmetric access charges. This paper is aimed at analysing the effectiveness of this regulatory measure, assuming that operators are differentiated in terms of brand loyalty and cost structure.     

Do small shareholders count?

We hypothesize that age similarity among small shareholders acts as an implicit coordinating device for their actions and, thus, could represent an indirect source of corporate governance in firms with dispersed ownership. We test this hypothesis on a sample of Swedish firms during the 1995-2000 period. Consistent with our hypothesis, we find that compared with shareholders of differing ages, same-age noncontrolling shareholders sell more aggressively following negative firm news; firms with more age-similar small shareholders are more profitable and command higher valuation; and an increase (decline) in a firm's small shareholder age similarity brings a significantly large increase (decline) in its stock price. The last effects are more pronounced in the absence of a controlling shareholder.     

Tax compliance under horizontal and vertical equity conditions: An experimental approach

Tax compliance is a complex phenomenon, which requires to be addressed from different perspectives. We report the results of a real-effort experiment aiming at testing the effect of different equity conditions on individual tax compliance levels. We show that equity considerations seem to change individual behaviour only when a vertically unfair tax system is implemented. Also, random effects Tobit estimations show that being audited in the previous period has a negative effect on tax evasion, whereas the level of the fine paid in the previous period positively affects income underreporting. Also, we find that when subjects are in the vertical inequity condition they are significantly more likely to fully evade taxes than in the equity condition, whereas such result cannot be found in the horizontal inequity condition. Finally, we find a standard gender effect showing that female participants are less likely to evade taxes than man and that risk aversion negatively affect tax evasion behaviour.