Economic theory is replete with causal hypotheses that are scarcely tested because economists are generally constrained to work with observational data. This article describes the use of causal inference methods for testing a hypothesis that one random variable causes another. Contingent on a...

Because of the recent soaring petroleum price and growing environmental concerns, biodiesel has become an important alternative fuel. Biodiesel is the mono alky esters made from a vegetable oil, such as soybean or rapeseed oil, or sometimes from animal fats. The escalation in world petroleum...

The 2005 food crisis centered in Niger received worldwide attention and extensive media coverage. Crops suffered from poor rainfall and were plagued by locusts throughout the growing season. Malnutrition flourished with the sudden disruption in food supplies. One-fifth of Niger's children...