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Study Overview

Fast-Tracking the Access to Improved and Popular Varieties of Root Crops by Smallholder Farmers: A Case of Sweetpotato and Cassava
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In Tanzania and Uganda, like in most of sub-Saharan Africa, about 70% of the population is composed of smallholder farmers in rural areas. Poverty alleviation in both countries is directly linked to agriculture, and the introduction of new agricultural technologies / practices that boost yield and nutritional intake have the potential to reduce poverty and hunger. In 2015, the Sugarcane Research Institute - Kibaha, under the Tanzania Ministry of Agriculture, Food Security, and Cooperatives (MAFC), and in collaboration with multiple partners in Uganda and Tanzania, launched a pilot project that seeks to boost the adoption of orange-flesh sweet potato (OFSP) and other improved varieties of sweet potato in Tanzania and Uganda. This project disseminates improved planting materials through primary school children in rural areas and accompanies dissemination with a suite of training and community mobilization activities. The International Institute of Tropical Agriculture (IITA) and IDinsight plan to evaluate the impact of the Fast Track project on uptake of OFSP using a randomized control trial. The evaluation will take place in both Tanzania and Uganda.

Registration Citation:

Kpaka, H.M. and Manyong, V., 2016. Fast-Tracking the Access to Improved and Popular Varieties of Root Crops by Smallholder Farmers: A Case of Sweetpotato and Cassava. Registry for International Development for Impact Evaluations (RIDIE). Available at: 10.23846/ridie099

Agriculture and Rural Development
Additional Keywords:
Root Crop, Adoption, Sweet Potato
Secondary ID Number(s):

Principal Investigator(s)

Name of First PI:
Henry Musa Kpaka
International Institute for Tropical Agriculture
Name of Second PI:
Victor Manyong
International Institute for Tropical Agriculture

Study Sponsor

Bill and Melinda Gates Foundation
Study Sponsor Location:
United States

Research Partner

Name of Partner Institution:
Type of Organization:
Private firm
United States

Intervention Overview


There are a number of supply side and demand side market inefficiencies that prevent farmers from adopting agricultural technologies. The Fast-Track program will address many of these inefficiencies by making available to farmers planting materials of improved varieties in a timely and cost-friendly manner. The Fast Track intervention consists of 4 activities: 1. Procurement: Implementers, which includes research station and extension officers in the districts will select a mix of four improved varieties to distribute at schools and will source the vines from trained vines multipliers and national research stations. 2. Distribution: Implementers will distribute “starter packs” of approximately 120 vines to 200 students per school. 3. Training: Implementers will share best agricultural practices with target communities through training sessions, farmer field days, demonstration plots, and nutrition information sessions. 4.“Give Double”: Implementers will nudge households that received vines through school distribution to give equivalent-sized “starter packs” to two neighbors

Theory of Change:
Multiple Treatment Arms Evaluated?

Implementing Agency

Name of Organization:
Sugarcane Research Institute-Kibaha Tanzania, and NaCCRI- Ugnada
Type of Organization:
Public Sector, e.g. Government Agency or Ministry

Program Funder

Name of Organization:
Bill and Melinda Gates Foundation
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Intervention Timing

Intervention or Program Started at time of Registration?
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Evaluation Method

Evaluation Method Overview

Primary (or First) Evaluation Method:
Randomized control trial
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Method Details

Details of Evaluation Approach:

This study is a clustered randomized control trial with one arm, where the treatment villages will receive the intervention activities and control villages none. For this evaluation we selected schools such that we have one school per village. The evaluation will take place in five separate districts in Tanzania and Uganda. Impact of the Fast Track program on uptake of improved sweet potato will be estimated by fitting logistic regressions to binary outcomes and linear regressions to continuous outcomes across evaluation arms while controlling for covariates such as size of household, primary/secondary involvement in the Fast Track program, prior usage of / access to improved vines, and access to water for maintaining vines. Analysis will be performed using Stata. Household survey data will be collected at baseline, before implementation in 2015, and at end line in 2016. A detailed protocol will be developed to identify improved varieties and quantify adoption rate. Analysis will be done using stata

Outcomes (Endpoints):

Primary Outcome: Uptake of OFSP (proportion of farmers in each village currently growing OFSP when survey takes place). Secondary Outcomes: Intensity of uptake of OFSP (which we will measure by the proportion of OFSP grown, both in terms of share of land area and the quantity of vines planted) . Tertiary Outcomes: Production of sweet potato, income from sweet potato, Vitamin A intake

Unit of Analysis:
Sixty villages in total, 40 treatment and 20 control. The unbalanceness is to provide an opportunity to look at a third arm.
Unit of Intervention or Assignment:
School, which roughly matches villages
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Size of Treatment, Control, or Comparison Subsamples:
Treatment: 40 schools, 797 households Control: 20 schools, 399 households

Supplementary Files

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Outcomes Data

A household survey will be used to collect all data. Administrative project data may be used to verify findings or add additional context. Baseline data was collected in November 2015 through January 2016. Endline data will be collected in November 2018
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Treatment Assignment Data

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Data Analysis

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Study Materials

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Registration Category

Registration Category:
Prospective, Category 1: Data for measuring impacts have not been collected

Completion Overview

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Preliminary Report:
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Data Availability

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Other Materials

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Description of Changes:

Study Stopped