In public good games, voluntary contributions tend to start off high and decline as the game is repeated. If high contributors are matched, however, contributions tend to stay high. We propose a formalization predicting that high contributors will self-select into groups committed to charitable...

In public good games, voluntary contributions tend to start off high and decline as the game is repeated. If high contributors are matched, however, contributions tend to stay high. We propose a formalization predicting that high contributors will self-select into groups committed to charitable...

The Nordic countries have the lowest maternal and child mortality rates in the world. This has not always been the case. In 1887 the mortality rates in Norway were similar to those of developing countries today. During the next 34 years, Norwegian maternal mortality was halved and infant...

Rain affects electoral turnout both through a direct effect on the cost of voting and by changing the opportunity cost. In a panel of Norwegian municipalities I find that rain on Election Day increases turnout. As turnout affects electoral outcomes, rain provides an exogeneous source of...

Rainfall is a truly exogeneous variable and hence popular as an instrument for many outcomes. But by its very nature, rainfall in nearby areas tends to be correlated. I show theoretically that if there are also spatial trends in outcomes of interest, this may create spurious correlation. In...

We show that the recent rise in Afghan opium production is caused by violent conflicts. Violence destroys roads and irrigation, crucial to alternative crops, and weakens local incentives to rebuild infrastructure and enforce law and order. Exploiting a unique data set, we show that Western...

No voters cast their votes based on perfect information, but better educated and richer voters are on average better informed than others. We develop a model where the voting mistakes resulting from low political knowledge reduce the weight of poor voters, and cause parties to choose political...

Rain affects electoral turnout both through a direct effect on the cost of voting and by changing the opportunity cost. In a panel of Norwegian municipalities I find that rain on Election Day increases turnout. As turnout affects electoral outcomes, rain provides an exogeneous source of...

No voters cast their votes based on perfect information, but better educated and richer voters are on average better informed than others. We develop a model where the voting mistakes resulting from low political knowledge reduce the weight of poor voters, and cause parties to choose political...

We show that the recent rise in Afghan opium production is caused by violent conflicts. Violence destroys roads and irrigation, crucial to alternative crops, and weakens local incentives to rebuild infrastructure and enforce law and order. Exploiting a unique data set, we show that Western...