There are 8 common extension approaches used by organizations worldwide: general, commodity specialized, training and visit, participatory agricultural, project, farming systems development, cost sharing, and educational institution. Each has different characteristics, assumptions about farmers, purposes, planning/implementation strategies, resource requirements, implementation strategies, and measures of success. The general approach is top-down and centralized, while participatory and farming systems are more decentralized and involve farmers. Commodity specialized and training and visit approaches focus on increasing specific crop yields. The project approach concentrates resources on a small area for a limited time.