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...

This paper shows one way of generalizing the standard framework of inequality measurement to allow for a distinction between fair and unfair inequalities. We introduce the unfairness Lorenz curve and the unfairness Gini, which are generalizations of the standard versions of the Lorenz curve and...

Definitions of equivalence scales are usually based on a household utility function. This may be founded on an assumption of the household maximizing a welfare function of individual utilities. Basing inter-household comparisons of welfare on this approach is fallacious because households put...

In public good games, voluntary contributions tend to start of 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 selfselect into groups committed to charitable...

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...

In many countries extreme poverty is unnecessary. Yet it persists. We propose a simple index, denoted the Miser index, to measure the extent to which societies have poverty in the midst of affluence. It builds on the generalized Lorenz curve, but can also be seen as a measure of polarization...