Cartels are inherently instable. Each cartelist is best off if it breaks the cartel, while the remaining firms remain loyal. If firms interact only once, if products are homogenous, if firms compete in price, and if marginal cost is constant, theory even predicts that strategic interaction...

In their majority, public international lawyers postulate that for a new rule of customary law to originate, two conditions must be fulfilled: there must be consistent practice, and it must be shown that this practice is motivated by the belief that such behaviour is required in law. Maurice...

For decades, experimental economics has been very interested in behavior that could be characterized as practicing solidarity (although the term is rarely used). Solidarity is a key concept in Catholic Social Teaching. This paper builds a bridge between these two endeavors that, thus far, had...

Sanctions are often so weak that a money maximizing individual would not be deterred. In this paper I show that they may nonetheless serve a forward looking purpose if sufficiently many individuals are averse against advantageous inequity. Using the Fehr/Schmidt model (QJE 1999) I define three...

The Internet globalizes the world. National regulatory autonomy shrinks. Transferring data from one country to another is almost costless. Foreign content is just a click away. Why is it that states have been able to re-install co-existence in some policy areas, and not in others? In data...

We study the interdependence of optimal tax and expenditure policies. An optimal policy requires that information on preferences is made available. We first study this problem from a general mechanism design perspective and show that efficiency is possible only if the individuals who decide on...

The literature on public goods has shown that efficient outcomes are impossible if participation constraints have to be respected. This paper addresses the question whether they should be imposed. It asks under what conditions efficiency considerations justify that individuals are forced to pay...

Broken Windows: the metaphor has changed New York and Los Angeles. Yet it is far from undisputed whether the broken windows policy was causal for reducing crime. In a series of lab experiments we show that first impressions are indeed causal for cooperativeness in three different institutional...

Does probation pay a double dividend? Society saves the cost of incarceration, and convicts preserve their liberty. But does probation also reduce the risk of recidivism? In a meta-study we show that the field evidence is inconclusive. Moreover it struggles with an identification problem: those...