Determining the efficacy of innovative distribution models of root crops

Client: Bill and Melinda Gates Foundation
Location: Tanzania, Uganda
Sector:  Agriculture 
Dates of service: 2014-2018
IDinsight service:
Impact evaluation; process evaluation
IDinsight contacts: Chris Chibwana
Status: Complete
Report: Fast-tracking the Access to Improved and Popular Varieties of Root Crops by Small Holder Farmers: A Case of Sweet Potato and Cassava

Cissy Kagalu of Mukono District, Uganda explains how many sweet potato vines she planted in her fields.

Cissy Kagalu of Mukono District, Uganda explains how many sweet potato vines she planted in her fields.

The Problem

More than 50 million smallholder farmers in sub-Saharan Africa struggle with poverty and hunger because their farms are not productive enough. Improved crop varieties can help boost the incomes of smallholder farmers, but disseminating them cost-effectively is a challenge.

The Fast Track Project, funded by the Bill and Melinda Gates Foundation, more cost-effectively distributes improved sweet potato varieties through a school-based approach. Students at public primary schools received “starter packs” of improved sweet potato vines and nutrition training, and were then asked to multiply vines and give similar “starter packs” to their neighbours.

The Fast Track Project wanted to determine the efficacy of a school-based approach to distributing improved vines to smallholder farmers, and refine the implementation of the program.

Evidence Needs

IDinsight Service

IDinsight, in collaboration with The Fast Track Project’s implementing partners and the International Institute of Tropical Agriculture (IITA), conducted a randomized controlled trial (RCT) in Tanzania and Uganda to evaluate the efficacy of the distribution approach. We also conducted two process evaluations, one during project piloting, and another during the main implementation stage.


The RCT results suggest that the Fast Track school-based model was effective. However, uptake and consumption of a particular variety— the Orange Flesh Sweet Potato, which has high levels of Vitamin A—was relatively limited. This suggest that this distribution approach can only partially address rural Vitamin A deficiency, a secondary objective for the Fast Track Project, and should be considered in combination with other approaches.