Working papers results

How can laboratory experiments help us understand banking crises, including the usefulness of various policy responses? After giving a concise introduction to the field of experimental economics more generally, I attempt to provide answers. I discuss methodological issues and survey relevant work that has been done.

Because journals favor clear stories researchers' may gain by engaging in scientific misconduct, ranging from shady practices like running more sessions hoping for significance to outright data fabrication. To set researchers' incentives straight, we propose sealed-envelope submissions, where editors' and referees' evaluations are based only on the interest of the research question and on the proposed empirical method.

We introduce imperfect information in stock prices determination. Agents receive a noisy signal about the structural shock driving future dividend variations. Equilibrium stock prices include a transitory 'noise bubble' which can be responsible for boom andbust episodes unrelated to economic fundamentals. We propose a non-standard VAR procedure to estimate impulse response functions to noise shock and the bubble component of stock prices. Noise explains a large fraction of US stock prices. The dot-com bubble is explained by noise. The 2007 stock price boom is not a bubble, whereas the following stock market crisis is due to negative noise shocks.

We investigate the role of 'noise' shocks as a source of business cycle fluctuations. To do so we set up a simple model of imperfect information and derive restrictions for identifying the noise shock in a VAR model. The novelty of our approach is that identification is reached by means of dynamic rotations of the reduced form residuals. We find that noise shocks generate hump-shaped responses of GDP, consumption and investment and account for quite a sizable fraction of their prediction error variance at business cycle horizons.

We build a model of a limit order book and examine the consequences of adding a dark pool. Starting with an illiquid book, we show that book and consolidated fill rates and volume increase, but the spread widens, depth declines and welfare deteriorates. When book liquidity increases, more orders migrate to the dark pool and large traders'welfare improves; but while the spread-increase is dampened, the depth-reduction is amplified and small traders are still worse off. All effects are stronger for a continuous than for a periodic dark pool and when the tick size is large.

IIf citizens of different countries belonging to an economic union adhere to different and deeply rooted cultural norms, when these countries interact their leaders may find it impossible to agree on efficient policies, especially in hard times. Political leaders' actions are bound to express policies that do not violate these norms. This paper provides a simple positive theory and a compelling case study of the importance of cultural clashes when economies integrate, as well as a normative argument about the desirability of institutional integration. Namely, we argue that a political union, with a common institutions and enforcement of rules, is a solution which is most beneficial the greater is cultural diversity in an economic union.

In deciding whether to join a coalition or not, an agent must consider both i) the expected power of the coalition and ii) her position in the vertical structure within the coalition. We establish the existence of a positive relationship between the degree of inequality in remuneration across ranks within coalitions and the number of coalitions to be formed endogenously in stable systems. An inherent feature of such coalitions is that they are mixed and balanced, rather than segregated, in terms of members abilities. When the surplus of a coalition is assumed to be linear in its relative power conditional on its size, we also establish the existence of stable systems and characterise them fully: a system is stable if and only if all coalitions are of an ecient size and every agent is paid her marginal contribution.

We consider a decision maker who ranks actions according to the smooth ambiguity criterion of Klibanoff et al. (2005). An action is justifiable if it is a best reply to some belief over probabilistic models. We show that higher ambiguity aversion expands the set of justifiable actions. In turn, this implies that higher ambiguity aversion expands the set of rationalizable actions of a game. Our results follow from a generalization of the duality lemma of Wald (1949) and Pearce (1984).

We analyze political selection in a closed list proportional system where parties have strong gate-keeping power, which they use as an instrument to pursue votes. Parties face a trade-off between selecting loyal candidates or experts, who are highly valued by the voters and thus increase the probability of winning the election. Voters can be rational or behavioral. The former care about the quality mix of the elected candidates in the winning party, and hence about the ordering on the party list. The latter only concentrate on the quality type of the candidates in the top positions of the party list. Our theoretical model shows that to persuade rational voters parties optimally allocate loyalists to safe seats and experts to uncertain positions. Persuading behavioral voters instead requires to position the experts visibly on top of the electoral list. Our empirical analysis, which uses data from the 2013 National election in Italy-held under closed list proportional representation-and from independent pre-electoral polls, is overall supportive of voters' rational behavior. Loyalists (i.e., party officers or former members of Parliament who mostly voted along party lines) are overrepresented in safe positions, and, within both safe and uncertain positions, they are ranked higher in the list.

Paul Krugman has written a very timely paper. It discusses an old issue, that has become very relevant again. My comments address two questions. First, should inflation targeting be reconsidered? Here my answer is a clear and resounding yes. Inflation targeting performed very well in the fight against inflation and in stabilizing inflation expectations. But now, even leaving issues of financial stability aside, monetary policy is faced with different challenges. Second, which features of the inflation targeting framework should be changed? Here I argue that other aspects of the framework are more important than the numerical value of the target. In addressing these questions, I review Paul Krugman's arguments, agreeing with many but not all of them.