The Tragedy of the Commons in Cote d'Ivoire Agriculture: Empirical Evidence and Implications for Evaluating Trade Policies
利用科特迪瓦1985-87年数据，通过理论模型分析土地耕种决策，发现农民未内生化生物质的外部成本，导致村庄收入损失高达14%，远超传统扭曲的估计。
Expansion of cultivated land diminishes the extent of forestlands or reduces the length of fallow periods and, hence, reduces the amount of natural vegetation. The increase in land under cultivation has a direct output-increasing effect at the cost of reducing natural capital and agricultural productivity. The evidence for western Côte d'Ivoire is consistent with, and provides an explanation for, the declining agricultural productivity observed in Sub-Saharan Africa during the past few decades. \nThis article uses a theoretical model to determine the level of land cultivation that maximizes village income, using data from Côte d'Ivoire for 1985–87. An important part of the land is under common property, usually at the village level. The results show that farmers do not internalize even a small fraction of the external cost of bio-mass in their land allocation decisions. The lack of internalization of the social cost of the biomass resource leads to large income losses at the village level—as much as 14 percent of village income. These losses are many times larger than the usual estimates for conventional distortions.