Working papers results

2016 - n° 583
In this paper, we run a laboratory experiment where the information set is relatively rich, and, in particular, it includes audits on other taxpayers. At the same time, the implementation of the Bayesian updating process for the subjective probability to be audited is fairly simple. By doing so, we are able to elicit a range of consistent but heterogeneous probability beliefs and to distinguish between Bayesian and non-Bayesian subjects. We obtain two major results concerning Bayesian subjects. First, they exhibit strong and robust short-run BoCE. Second, they are seemingly not affected by audits on other taxpayers in their compliance decision. These results are robust to different definitions of Bayesianity and to different specifications. They conflict with the evidence that Bayesian agents do perceive correctly the chance to be audited. In turn, this suggests that existing explanations of the BoCE are not entirely satisfactory and that alternative theories, possibly based on the Duality approach, are needed.

Luigi Mittone, Fabrizio Panebianco, Alessandro Santoro
Keywords: Bomb-crater effect, Bayesian Updating, Behavioral Duality
2016 - n° 582
We investigate how Internal Labor Markets (ILMs) allow organizations to accommodate shocks calling for costly labor adjustments. Using data on workers' mobility within French business groups, we find that adverse shocks affecting affliated firms boost the proportion of workers redeployed to other group units rather than external firms. This effect is stronger when labor regulations are stricter and destination-firms are more efficient or enjoy better growth opportunities. Affiliated firms hit by positive shocks rely on the ILM for new hires, especially high-skilled workers. Overall, ILMs emerge as a co-insurance mechanism within organizations, providing job stability to employees as a by-product.

Giacinta Cestone, Chiara Fumagalli, Francis Kramarz, Giovanni Pica
Keywords: Internal Labor Markets, Organizations, Business Groups
2016 - n° 581
The risk-neutral pricing formula provides the valuation of random payoffs in continuous-time markets. Despite the variety of payoffs, no arbitrage price dynamics are driven by the same (possibly stochastic) interest rate. We formalize this intuition by showing that no arbitrage prices constitute the solution of a differential equation, where interest rates are prominent. To achieve this goal, we introduce the notion of weak time-derivative, which permits to differentiate adapted processes. This instrument isolates drifts of semimartingales and it is null for martingales. Finally, we reformulate the eigenvalue problem of Hansen and Scheinkman (2009) by employing weak time-derivatives.

Massimo Marinacci and Federico Severino
Keywords: no arbitrage pricing; weak time-derivative; martingale component; special semimartingales; stochastic interest rates
2016 - n° 580
We experimentally test the impact of expanding access to basic bank accounts in Uganda, Malawi, and Chile. Over two years, 17%, 10%, and 3% of treatment individuals made five or more deposits, respectively. Average monthly deposits for them were at the 79th, 91st, and 96th percentiles of baseline savings. Survey data show no clearly discernible intention-to-treat effects on savings or any downstream outcomes. This suggests that policies merely focused on expanding access to basic accounts are unlikely to improve welfare noticeably since impacts, even if present, are likely small and diverse.

Pascaline Dupas, Dean Karlan, Jonathan Robinson, and Diego Ubfal
Keywords: financial access; savings; banking; micro-finance; field experiment; multicountry; Uganda; Malawi; Chile
2016 - n° 579
Consider a network of firms where a firm T is given the opportunity to innovate a product (first-generation innovation). If successful, this firm can temporarily sell this innovation to her direct neighbors because this will give her access to a larger market. However, if her direct neighbors innovate themselves on top of firm T's innovation (second-generation innovations), then firm T loses the right to sell her initial innovation to the remaining firms in the market. We analyze this game where each firm (T and her direct neighbors) has to decide at which price they want to sell their innovation. We show that the optimal price policy of each firm depends on the level of property rights protection, the position of firm T in the network, her degree and the size of the market. We then analyze the welfare implications of our model where the planner that maximizes total welfare has to decide which firm to target. We show that it depends on the level of property rights protection and on the network structure in a non-trivial way.

Fabrizio Panebianco, Thierry Verdier, Yves Zenou
Keywords: Networks, diffusion centrality, targets, innovation
2016 - n° 578
We study from a preferential viewpoint absolute and relative attitudes toward ambiguity determined by wealth effects. We provide different characterizations of these attitudes for a large class of preferences: monotone and continuous preferences which satisfy risk independence. We specify our results for different subclasses of preferences.
S. Cerreia-Vioglio, F. Maccheroni, and M. Marinacci
2016 - n° 577
Pre-Hilbert A-Modules are a natural generalization of inner product spaces in which the scalars are allowed to be from an arbitrary algebra. In this perspective, submodules are the generalization of vector subspaces. The notion of orthogonality generalizes in an obvious way too. In this paper, we provide necessary and sufficient topological conditions for a submodule to be orthogonally complemented. We present three applications of our results. In the most important one, we obtain the Kunita-Watanabe decomposition for conditionally square-integrable martingales as an orthogonal decomposition result carried out in an opportune pre-Hilbert A-module. Second, we show that a version of Stricker's Lemma can be also derived as a corollary of our results. Finally, we provide a version of the Koopman-von Neumann decomposition theorem for a specific pre-Hilbert module which is useful in Ergodic Theory.
S. Cerreia-Vioglio, F. Maccheroni, and M. Marinacci
2016 - n° 576
The results of an experiment extending Ellsberg's setup demonstrate that attitudes towards ambiguity and compound uncertainty are closely related. However, this association is much stronger when the second layer of uncertainty is subjective than when it is objective. Provided that the compound probabilities are simple enough, we find that most subjects, consisting of both students and policy makers, (1) reduce compound objective probabilities, (2) do not reduce compound subjective probabilities, and (3) are ambiguity non-neutral. By decomposing ambiguity into risk and model uncertainty, and jointly eliciting the attitudes individuals manifest towards these two types of uncertainty, we characterize individuals' degree of ambiguity aversion. Our data provides evidence of decreasing absolute ambiguity aversion and constant relative ambiguity aversion.

Loic Berger and Valentina Bosetti
Keywords: Ambiguity aversion, model uncertainty, reduction of compound lotteries, nonexpected utility, subjective probabilities, decreasing absolute ambiguity aversion
2016 - n° 575
This paper investigates the differential response of male and female voters to competitive persuasion in political campaigns. We implemented a survey experiment during the (mixed gender) electoral race for mayor in Milan (2011), and a field experiment during the (same gender) electoral race for mayor in Cava de' Tirreni (2015). In both cases, a sample of eligible voters was randomly divided into three groups. Two were exposed to either a positive or a negative campaign by one of the opponents. The third-control-group received no electoral information. In Milan, the campaigns were administered online and consisted of a bundle of advertising tools (videos, texts, slogans). In Cava de' Tirreni, we implemented a large scale door-to-door campaign in collaboration with one of the candidates, randomizing positive vs. negative messages. In both experiments, stark gender differences emerge. Females vote more for the opponent and less for the incumbent when they are exposed to the opponent's positive campaign. Exactly the opposite occurs for males. These gender differences cannot be accounted for by gender identification with the candidate, ideology, or other observable attributes of the voters.

Vincenzo Galasso and Tommaso Nannicini
Keywords: gender differences, political campaigns, randomized controlled trials, competitive persuasion
2016 - n° 574
In this article, we provide novel survey evidence on mid schoolers' awareness and ambiguity perceptions and on how such perceptions evolve during the process of high school track choice. Children in our study display partial awareness about the set of available tracks. Additionally, children report substantial belief ambiguity about their likelihood of a regular high school path, especially for lower-ranked tracks. Students start 8th grade with greater information about their favorite alternatives and continue to concentrate their search on the latter during the months before pre-enrollment. Children from less advantaged families display lower initial perceived knowledge and acquire information at a slower pace, particularly about college-preparatory schools.

Pamela Giustinelli and Nicola Pavoni
Keywords: Subjective Beliefs, Learning under Ambiguity and Limited Awareness, School Choice
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