Access, adoption, and diffusion: understanding the long-term impacts of improved vegetable and fish technologies in Bangladesh

This paper assesses long-term impacts of early adoption of vegetable and polyculture fish production technologies on household and individual well-being in Bangladesh. In 1996-1997 and 2006-2007, a panel of households were surveyed in three sites where non-governmental organisations and extension programmes disseminated agricultural technologies. Using nearest-neighbour matching to construct a statistical comparison group, the authors find that long-term impacts differ across agricultural technology interventions and across outcomes. Long-term impacts on household-level consumption expenditures and asset accumulation are, in general, insignificant in the improved vegetables sites, but are positive and significant in the individually operated fish ponds sites. However, the impacts on individual nutrient intake, nutrient adequacy, and nutritional status do not follow the pattern of household-level impacts. Differences in long-term and short-term impacts arise from several causes: differences in dissemination and targeting mechanisms that may affect household-level adoption decisions; initial differences between comparison and treatment groups; divisibility and ease of dissemination of the technology; and intrahousehold allocation processes that determine the allocation of gains from the new technology among household members.