Mediation analysis of the impact of the Zimbabwe Harmonized Social Cash Transfer Programme on food security and nutrition

•The paper studies the effects of the Harmonized Social Cash Transfer programme on food security and nutrition.•The total effect ranges between a 11 and 16 percent increase with respect to the baseline mean for the dietary diversity score and the number of food items consumed, respectively.•The mediation analysis disentangles the total effect into direct and indirect effect (mediated by agricultural activities)•Between 10 and 21 percent of the total effect is mediated by agricultural activities.•The programme contributes to household welfare by guaranteeing beneficiaries a higher purchasing power and by boosting their agricultural activities.