Evaluating Impacts of GIFT Adoption at Scale: Understanding the Dissemination Process from Hatcheries to Farmers in Bangladesh

The performance of GIFT in various contexts has been demonstrated through on-station and on-farm evaluations. Evidence indicates that adoption of GIFT can increase fish yields hence economic returns for farmers; increase survival rate, shorten harvest time and increase individual harvesting weight; reduce production and operational costs; and reduce local fish market prices improving affordability among consumers. While some of these possible impact mechanisms are relatively well understood, the challenge faced in all impact evaluations is the establishment of a convincing counterfactual without which it is impossible to infer causality. Yet understanding the impacts of GIFT is important to inform and guide policy and investment efforts not only to address future food requirements, but also in terms of broader societal visions. Therefore, the objectives of this study were twofold: (1) to describe and document the dissemination process for GIFT via hatcheries to farmers and the implications for how a hatchery “catchment area” could be defined conceptually and empirically in the context of an impact assessment study; and (2) to validate the catchment areas as defined by hatchery data by collecting data directly from farms/farmers. The study was conducted in Bangladesh with funding from the Standing Panel on Impact Assessment (SPIA) in order to provide the required information for an accurate characterization and documentation of GIFT dissemination in Bangladesh to inform proper construction of the counterfactual for a deep impact study.

吉富罗非鱼（GIFT）在多种场景下的应用效果，已通过站内试验与田间农户试验得到验证。研究证据表明，推广GIFT可提升鱼类养殖产量，进而增加农户经济收益；同时可提高鱼苗成活率、缩短养殖收获周期，并提升单尾收获体重；还能降低生产与运营成本，同时压低当地鱼类市场售价，提升消费者的购买可及性。尽管其中部分潜在影响机制已得到较为充分的阐释，但所有影响评估均面临的核心挑战在于如何构建令人信服的反事实框架，缺乏该框架则无法推断因果关系。然而，明晰GIFT的影响效应，对于指导政策制定与投资实践至关重要——这不仅关乎未来粮食需求的保障，也契合更广泛的社会发展愿景。因此，本研究的目标分为两部分：(1) 系统描述并记录GIFT通过育苗场向农户推广的传播流程，以及在影响评估研究框架下，如何从概念与实证层面界定育苗场“覆盖区（catchment area）”；(2) 通过直接从养殖场/农户处采集数据，验证基于育苗场数据界定的覆盖区合理性。本研究由影响评估常设小组（Standing Panel on Impact Assessment, SPIA）资助，在孟加拉国开展，旨在为精准刻画并记录GIFT在孟加拉国的推广传播过程提供必要信息，以助力后续深度影响研究中反事实框架的合理构建。