Impact of home garden interventions in East Africa: Results of three randomized controlled trials
基于肯尼亚、坦桑尼亚和乌干达的家庭菜园推广项目数据，通过三项随机对照试验发现，干预仅显著增加了坦桑尼亚的蔬菜生产和收获时长，但对饮食无显著影响，与亚洲的积极效果形成对比。
Sub-Saharan Africa has the lowest per capita consumption of vegetables of all regions in the world. As low vegetable consumption is associated with poor human health, there is need for effective policies and interventions to increase it. Home garden interventions have proven effective in several countries in Asia, but evidence from large trials is scant in Africa. Using data from a home garden promotion project in Kenya, Tanzania and Uganda, this study tests the hypothesis that home garden interventions, offered to rural households with women 14–35 years of age and/or with children under five years of age, increase household production and consumption of vegetables. Three randomized controlled trials collected pre- and post-intervention data (2 years apart) for 1,255 intervention and control households. We report intent-to-treat effects and the treatment effect on the treated and analyze distributional effects using quantile regression. For Tanzania, the results show a 20% increase in households producing vegetables and an additional two months of vegetable harvesting, but no such significant effects were found for Kenya and Uganda. We find no significant effects on diets. Lack of impact may be explained from the fact that many participating households were already producing vegetables (reducing the scope for impact) and a low participation rate of selected households in training events. These results stand in contrast to the positive impacts of home garden interventions in Asia. The results suggest a need to better understand barriers to home garden interventions in the three countries and a need for more careful design, local adaptation and targeting.