Working papers results

During the 2020 Corona virus crisis in Lombardy -a stranger time- the Game Design Workshop at Bocconi University studied the implementation of the algorithms proposed by Maccheroni (2020, SSRN paper 3622663) for digital play using only six-sided dice. Swords & Wizardry by Finch (2011, Frog God Games) is a popular restatement of the Original Dungeons & Dragons Game by Gygax and Arneson (1974, Tactical Studies Rules). A case study, the present paper presents an implementation of the aforementioned algorithms for this game.

The paper develops a foundational model of the decentralized allocation of subsidies through competitive grantmaking. Casting the problem in a simple supply and demand framework, we characterize the equilibrium acceptance standard and applications. The equilibrium success rate (grants over applications) decreases in the budget, consistent with some recent evidence, if and only if the distribution of types has decreasing hazard rate. In all stable equilibria resulting when funds are allocated across fields proportionally to applications-as well as under apportionment rules in a general class characterized in the paper-an increase in noise in the evaluation in a field perversely raises applications in that field and reduces applications in all the other fields. We characterize how the design of allocation rules can be modified to improve welfare.

Lower costs of international trade affect both firms' innovation incentives and theirmarket power. We develop a dynamic general equilibrium model with endogenous innovation and endogenous markups to study the interaction between these effects. Lower trade costs stimulate innovation by large firms that are technologically close to their rivals. However, as innovators increase their productivity advantage over others, they also increase their markups. Our calibrated model suggests that a fall in trade costs which increases the trade-to-GDP ratio of the US manufacturing sector from 12% (its level in the 1970s) to 24% (its current level) increases productivity growth by 0.12 percentage points and the aggregate markup by 1.70 percentage points. Without the feedback effect of innovation on the productivity distribution, markups would actually have fallen.

This paper studies electoral competition over redistributive taxes between a safe incumbent and a risky opponent. As in prospect theory, economically disappointed voters become risk lovers, and hence are intrinsically attracted by the more risky candidate. We show that, after a large adverse economic shock, the equilibrium can display policy divergence: the more risky candidate proposes lower taxes and is supported by a coalition of very rich and very disappointed voters, while the safe candidate proposes higher taxes. This can explain why new populist parties are often supported by economically dissatisfied voters and yet they run on economic policy platforms of low redistribution. We show that survey data on the German SOEP are consistent with our theoretical predictions on voters' behavior.

We present a theory of war onset and war duration in which power is multidimensional and can evolve through conflict. The resources players can secure without fighting are determined by their political power, while the ability of appropriating resources with violence is due to their military power. When deciding whether to wage a war, players evaluate the consequences on the current allocation of resources as well as on the future distribution of military and political power. We deliver three main results: a key driver of war is the mismatch between military and political power; dynamic incentives may amplify static incentives, leading forward-looking players to be more belligerent; and a war is more likely to last for longer if political power is initially more unbalanced than military power and the politically under-represented player is militarily advantaged. Our results are robust to allowing the peaceful allocation of resources to be a function of both political and military power. Finally, we provide empirical correlations on inter-state wars that are consistent with the theory.

We use decision theory to confront uncertainty that is sufficiently broad to incorporate 'models as approximations'.We presume the existence of a featured collection of what we call 'structured models' that have explicit substantive motivations. The decision maker confronts uncertainty through the lens of these models, but also views these models as simplifications, and hence, as misspecified. We extend min-max analysis under model ambiguity to incorporate the uncertainty induced by acknowledging that the models used in decision-making are simplified approximations. Formally, we provide an axiomatic rationale for a decision criterion that incorporates model misspecification concerns.

We use a recently developed right-tail variation of the Augmented Dickey-Fuller unit root test to identify and date-stamp periods of mildly explosive behavior in the weekly time series of eight U.S. fixed income yield spreads between September 2002 and April 2018. We find statistically significant evidence of mildly explosive dynamics in six of these spreads, two of which are short/medium-term mortgagerelated spreads. We show that the time intervals characterized by instability that we estimate from these yield spreads capture known episodes of financial and economic distress in the U.S. economy. Mild explosiveness migrates from short-term funding markets to medium- and long-term markets during the Great Financial Crisis of 2007-09. Furthermore, we statistically validate the conjecture that the initial panic of 2007 migrated from segments of the ABX market to other U.S. fixed income markets in the early phases of the financial crisis.

Policymaking during a pandemic can be extremely challenging. As COVID-19 is a new disease and its global impacts are unprecedented, decisions need to be made in a highly uncertain, complex and rapidly changing environment. In such a context, in which human lives and the economy are at stake, we argue that using ideas and constructs from modern decision theory, even informally, will make policymaking more a responsible and transparent process.

This paper investigates the effect of terrorism financing and recruitment on attacks. A Sharia-compliant institution in Pakistan induces exogenous variation in the funding of terrorist groups through their religious affiliation. I isolate the supply of terrorist attacks by following multiple terrorist groups with different affiliations operating in various cities. Higher terrorism financing, in a given location and period, generates more attacks in the same location and period. This effect increases in recruitment, measured through darkweb data, inputs by two judges and machine-learning. This evidence is consistent with terrorist organizations facing financial frictions to their internal capital market.

Negative advertising is frequent in electoral campaigns, despite its ambiguous effectiveness: negativity may reduce voters' evaluation of the targeted politician but have a backlash effect for the attacker. We study the effect of negative advertising in electoral races with more than two candidates with a large scale field experiment during an electoral campaign for mayor in Italy and a survey experiment in a fictitious mayoral campaign. In our field experiment, we find a strong, positive spillover effect on the third main candidate (neither the target nor the attacker). This effect is confirmed in our survey experiment, which creates a controlled environment with no ideological components nor strategic voting. The negative ad has no impact on the targeted incumbent, has a sizable backlash effect on the attacker, and largely benefits the idle candidate. The attacker is perceived as less cooperative, less likely to lead a successful government, and more ideologically extreme.