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AMS Acta (11.650 recursos)

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  1. Identification and estimation issues in Structural Vector Autoregressions with external instruments

    Angelini, Giovanni; Fanelli, Luca
    In this paper we discuss general identification results for Structural Vector Autoregressions (SVARs) with external instruments, considering the case in which r valid instruments are used to identify g ≥ 1 structural shocks, where r ≥ g. We endow the SVAR with an auxiliary statistical model for the external instruments which is a system of reduced form equations. The SVAR and the auxiliary model for the external instruments jointly form a `larger' SVAR characterized by a particularly restricted parametric structure, and are connected by the covariance matrix of their disturbances which incorporates the `relevance' and `exogeneity' conditions. We discuss identification...

  2. Shortened persistent homology for a biomedical retrieval system with relevance feedback

    Angeli, Alessia; Ferri, Massimo; Monti, Eleonora; Tomba, Ivan
    This is the report of a preliminary study, in which a new coding of persistence diagrams and two relevance feedback methods, designed for use with persistent homology, are combined.

  3. Parameter heterogeneity, persistence and cross-sectional dependence: new insights on fiscal policy reaction functions for the Euro area

    Golinelli, Roberto; Mammi, Irene; Musolesi, Antonio
    A number of novelties have emerged in the study of the discretionary fiscal policy within the Euro area during the last decade. Among the others, the availability of up-to-date information on fiscal indicators for the years following the Great Recession, the introduction of cutting-edge econometric methods, and a renewed interest about the sustainability of fiscal policy and public debt. The aim of this paper is to address the challenges posed by the estimation of the discretionary fiscal reaction function for the Euro area. We exploit recently introduced testing and estimation strategies for heterogeneous dynamic panels with cross-sectional dependence and propose...

  4. Testing Rational Addiction: When Lifetime is Uncertain, One Lag is Enough

    Dragone, Davide; Raggi, Davide
    The rational addiction model is usually tested by estimating a linear second-order difference Euler equation, which may produce unreliable estimates. We show that a linear first-order difference equation is a better alternative. This empirical specification is appropriate under the reasonable assumption that people are uncertain about the time of their death, it is based on the same structural assumptions used in the literature, and it retains all policy implications of the deterministic rational addiction model. It is also empirically convenient because it is simple, it allows using efficient estimation strategies that do not require instrumental variables, and it is robust...

  5. Between preferences and references: Evidence from Great Britain on asymmetric price elasticities

    Cornelsen, Laura; Mazzocchi, Mario; Smith, Richard
    Canonical demand studies and fiscal policy simulations rest on the assumption that consumers react symmetrically to price increases and decreases. We propose a theoretically consistent demand system which allows for asymmetric response by incorporating reference prices into both own- and cross-prices. Applying the system to a large and detailed home-scan household-level data-set with food prices and purchases from Great Britain, we show evidence on asymmetric consumer response and loss aversion, with a stronger response when prices rise above their reference level. Results are robust to changes in the price definition and model speci�cation, and a simulation shows that ignoring asymmetry may...

  6. Disentangling the effect of waiting times on hospital choice: Evidence from a panel data analysis

    Lippi Bruni, Matteo; Ugolini, Cristina; Verzulli, Rosella
    This study examines the effect of waiting times on hospital choice by using patient-level data on elective Percutaneous Transluminal Coronary Angioplasty (PTCA) procedures in the Italian NHS over the years 2008-2011. We perform a multinomial logit analysis including conditional logit and mixed logit specifications. Our findings show the importance of jointly controlling for time-invariant and time varying dimensions of hospital quality in order to disentangle the effect of waiting times on hospital choice. We provide evidence that patients are responsive to changes in waiting times and aspects of clinical quality within hospitals over time, and estimate the trade-off that patients...

  7. On the (in)stability of nonlinear feedback solutions in a dynamic duopoly with renewable resource exploitation

    Lambertini, Luca; Mantovani, Andrea
    We revisit Fujiwaraís (2008) differential duopoly game to show that the degenerate nonlinear feedback identified by the tangency point with the stationary state line is indeed unstable, given the dynamics of the natural resource exploited by firms. To do so, we fully characterise the continuum of nonlinear feedback solution via Rowat's (2007)method, characterising the infinitely many stable nonlinear feedback equilibria.

  8. When perfectionism becomes willpower

    Pennesi, Daniele
    Perfectionism can be healthy: striving for perfection requires the ability to selfregulate, namely willpower. This paper formalizes the intuitive relation between healthy perfectionism and willpower in the presence of temptation. The value of a menu of options for an individual with limited willpower corresponds to the lower bound of the value assigned to the same menu by a perfectionist, when temptation and perfectionism intensities are free to vary. Moreover, the higher the perfectionism strive, the higher the willpower. The relation between overwhelming temptation and the Strotz model is a particular case of the result. When there is uncertainty about temptation, we generalize Dekel and Lipman (2012) providing conditions...

  9. Gender quotas or girls’ networks? Towards an understanding of recruitment in the research profession in Italy

    Checchi, Daniele; Cicognani, Simona; Kulic, Nevena
    This article investigates the role of the gender composition of selection committees and networks in promoting women in research activities. We exploit a novel data set on recruitment processes at entry-level research positions in a leading Italian research centre that mainly operates in hard science. We find some evidence of discrimination against women at non-tenured entry levels, which is attenuated (or even reversed) by the presence of a woman on the selection committee. However, the most important predictor for recruitment seems to be previous connections with the research centre, which also serves as an important mechanism for women to enter...

  10. Monitoring institutions in indefinitely repeated games

    Camera, Gabriele; Casari, Marco
    Does monitoring past conduct facilitate intertemporal cooperation? We designed an experiment characterized by strategic uncertainty and multiple equilibria where coordinating on the efficient outcome is a challenge. Participants, interacting anonymously in a group, could pay a cost either to obtain information about their counterparts, or to create a freely available public record of individual conduct. Both monitoring institutions were actively employed. However, groups were unable to attain higher levels of cooperation compared to a treatment without monitoring. Information about past conduct alone thus appears to be ineffective in overcoming coordination challenges.

  11. Money and the Scale of Cooperation

    Bigoni, Maria; Camera, Gabriele; Casari, Marco
    This study reveals the existence of a causal link between the availability of money and an expanded scale of interaction. We constructed an experiment where participants chose the group size, either a low-value partnership or a high-value group of strangers, and then faced an intertemporal cooperative task. Theoretically, a monetary system was inessential to achieve cooperation. Empirically, without a working monetary system, participants were reluctant to expand the scale of interaction; and when they did, they ended up destroying surplus compared to partnerships, because cooperation collapsed in large groups. This economic failure was reversed only when participants managed to concurrently develop...

  12. Parabolic Cylinders and Folk Theorems

    Delbono, Flavio; Lambertini, Luca
    We study a class of games featuring payoff functions being parabolic cylinders where best reply functions are orthogonal and therefore the pure-strategy non-cooperative solution is attained as a Nash equilibrium in dominant strategies. We prove that the resulting threshold of the discount factor above which implicit collusion on the Pareto frontier is stable in the infinite supergames is independent of the number of players. This holds irrespective of whether punishment is based on infinite Nash reversion or one-shot stick-and-carrot strategy. We outline two examples stemming from economic theory and one from international relations.

  13. Writing off, Restructuring or Refinancing the Debt? The IMF’s role in the Greek Debt Crisis

    Manasse, Paolo
    This paper looks at the recent debt crisis in Greece and argues that the crisis exemplifies a sequence of systematic mistakes made by International Financial Institutions, mistakes whose consequences had been clearly anticipated at the time of the first bail-out and could have been avoided. I will argue that the “original sin” of international creditors has been that of refinancing, rather than partially writing off, the debt. This mistake has led to excessively restrictive policies, and has ultimately to interventions of bail-out/in much larger than those which would have solved the problem at the outset, causing unnecessary pain to the economy...

  14. Price Changes in Regulated Healthcare Markets: Do Public Hospitals Respond and How?

    Verzulli, Rossella; Fiorentini, Gianluca; Lippi Bruni, Matteo; Ugolini, Cristina
    This paper examines the behaviour of public hospitals in response to the average payment incentives created by price changes for patients classified in different Diagnosis Related Groups (DRGs). Using panel data on public hospitals located within the Italian region of Emilia-Romagna, we test whether a one-year increase in DRG prices induced public hospitals to increase their volume of activity, and whether a potential response is associated with changes in waiting times and/or length of stay. We find that public hospitals reacted to the policy change by increasing the number of patients with surgical treatments. This effect was smaller in the two years after the policy change than...

  15. La dama boba

    Vega, Lope de; Presotto, Marco (Ed.)
    Edizione critica di una commedia di Lope de Vega, con apparato di varianti e note di commento.

  16. Price Effects in the Short and in the Long Run

    Dragone, Davide; Vanin, Paolo
    We study a broad class of dynamic consumer problems and characterize the short and long-run response of the demand for a good to a permanent increase in its market price. Such response can be non-monotonic over time, and the short and long-run price-elasticity of demand may have opposite sign. This is a testable prediction and can arise even in the absence of income effects. Our results are robust to a variety of settings that are commonly used in the economic literature, and have relevant policy implications. We provide illustrative applications to models of human capital and labor supply, addiction, habit and taste formation, health capital, and renewable resources.

  17. Building a Structural Model: Parameterization and Structurality

    Mouchart, Michel; Orsi, Renzo
    A specific concept of structural model is used as a background for discussing the structurality of its parameterization. Conditions for a structural model to be also causal are examined. Difficulties and pitfalls arising from the parameterization are analyzed. In particular, pitfalls when considering alternative parameterizations of a same model are shown to have lead to ungrounded conclusions in the literature. Discussion of observationally equivalent models related to different economic mechanisms are used to make clear the connection between an economicall meaningful parameterization and an economically meaningful decomposition of a complex model. The design of economic policy is used for drawing some...

  18. On the private and social desirability of mixed bundling in complementary markets with cost savings

    Halmenschlager, Christine; Mantovani, Andrea
    The aim of this paper is to study both the private and the social desirability of a mixed bundling strategy that generates a cost savings effect. We confirm that mixed bundling is the dominant strategy for multiproduct firms, although it may give rise to a prisoner’s dilemma. Moreover, we show that mixed bundling may maximise social welfare, provided that cost savings are sufficiently high. Finally, we highlight the parametric regions where the social and the private interests coincide, and those where they do not. The recent evolution of broadband telecommunications services provides an ideal framework to apply our theoretical predictions.

  19. Terrorism Risk and Democratic Preferences in Pakistan

    Ur Rehman, Faiz; Vanin, Paolo
    Beyond direct damages, terrorism creates fear and insecurity, potentially reducing support for democratic institutions if these are deemed inadequate to tackle the threat, and increasing support for military governments. To investigate this possibility, we use data from Pakistan, a country that experienced an exponential rise in terrorism since 2001. Exploiting individual level data on democratic attitudes and district level information on terrorist attacks, we document that persistent exposure to terrorism (and more broadly to violence) is associated to a significantly lower support for democratic values. Results are robust to the inclusion of different sets of controls, to sample splits based on...

  20. Caesarean section and the manipulation of exact delivery time

    Fabbri, Daniele; Monfardini, Chiara; Castaldini, Ilaria; Protonotari, Adalgisa
    Physicians are often alleged responsible for the manipulation of delivery timing. We investigate this issue in a setting that negates the influence of financial incentives behind “physician’s demand induction” but allows for “risk aversion” to medical errors and “demand for leisure” motivations. Working on a sample of women admitted at the onset of labor in a big public hospital in Italy we estimate a model for the exact time of delivery as driven by individual indication to receive Caesarean Section (CS) and covariates. We find that ICS does not affect the day of delivery but leads to a circadian rhythm in the likelihood of delivery. The...

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