However, these sources of productivity gains usually do not have much connection to what is going on in the rest of the economy, and often can be utilised by relatively small number of farmers. They are like donations, better to have than not, but they depend less on a dynamic non-farm economy. However, agricultural productivity is also driven in some sub-sectors by dynamic developments in the non-farm sector, for example due to increasing demand for higher value-added products (especially in the context of the supermarket revolution), and due to reduced marketing and transaction costs from improved financial, transport and telecommunications markets.