Orange-Fleshed Sweet Potatoes (OFSP): Impact of Nutrition-Sensitive Agricultural Programs to Women Smallholder Farmers in Uganda

Last registered on January 21, 2021


Trial Information

General Information

Orange-Fleshed Sweet Potatoes (OFSP): Impact of Nutrition-Sensitive Agricultural Programs to Women Smallholder Farmers in Uganda
Initial registration date
January 21, 2021

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
January 21, 2021, 3:17 PM EST

First published corresponds to when the trial was first made public on the Registry after being reviewed.



Primary Investigator

World Bank

Other Primary Investigator(s)

PI Affiliation
University of Sydney
PI Affiliation
BRAC International
PI Affiliation
World Bank

Additional Trial Information

On going
Start date
End date
Secondary IDs
This study is an impact evaluation of the introduction of a nutrient-rich crop to women smallholder farmers in Uganda. The orange-fleshed sweet potato (OFSP) crop is biofortified with Vitamin-A and therefore expected to improve the nutritional outcomes of women and children in targeted households. The study employs a clustered randomized control trial (RCT) design covering a large sample of 8,400 households across 210 villages to test the relative efficacy of various interventions to relax adoption constraints of the OFSP crop to women farmers. A series of bundled and standalone treatment conditions address the following hypothesized constraints to adoption: resource, information, credit, time inconsistency, and price risk.
External Link(s)

Registration Citation

Buehren, Niklas et al. 2021. "Orange-Fleshed Sweet Potatoes (OFSP): Impact of Nutrition-Sensitive Agricultural Programs to Women Smallholder Farmers in Uganda." AEA RCT Registry. January 21.
Experimental Details


The interventions were implemented by BRAC Uganda (an NGO) as part of the project: “An Innovative, Integrated Approach to Enhance Smallholder Family Nutrition.” There are three sets of interventions that were implemented under this project: a) free orange-fleshed sweet potato (OFSP) inputs and agriculture extension, b) health and nutrition information, and c) innovative financial products, including: credit, input vouchers and price insurance.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Primary Outcomes are those relating to the marketability, productivity, knowledge, and adoption of OFSP. These may include but are not limited to: adoption of OFSP binary (cultivating any OFSP), productivity of OFSP and other crops, improved input use and intensity, sale of OFSP, degree of market participation/agricultural marketing. Respondent recall over a period of two cropping seasons will be used to measure primary indicators.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes are those relating to consumption and utilization of OFSP, as well as other health behavior change. For example, household consumption of OFSP and dietary diversity (24 hour recall); and nutritional impact of consuming OFSP and having access to services provided by a CHP. Anthropometric data (height- and weight-for age) of under-5s, as well as overall household food security will also be examined.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The study employs a clustered randomized control trial (RCT) design in order to estimate the treatment effects on the outcomes of interest. A total of 210 villages were randomly assigned to different treatment conditions: 30 villages to each village-level treatment arm over six treatments (180 villages) and one control group (30 villages).

In “T1: Agriculture Only”, 30 villages are assigned to receive free inputs for biofortified orange-fleshed sweet potatoes (OFSP) and agricultural extension in Season 1 of the intervention period. The “T2” treatment arms include bundling the agriculture intervention as in T1 with additional health and nutrition information (120 villages are randomly assigned to T2). Within T2, there are four sub-treatment groups: “T2a” 30 villages to agriculture and health/nutrition information bundled without any financial product ; “T2b” 30 to the bundle plus agricultural credit, “T2c” 30 to the bundle plus input vouchers, and “T2d” 30 to the bundle plus price insurance. In T3, 30 villages are randomly assigned to receive only the health and nutrition information components of the intervention. In the control group, 30 villages are randomly assigned to receive no interventions for the period of the study.

Experimental Design Details
Randomization Method
Randomization completed on Stata in the office.
Randomization Unit
Village level randomization
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
210 villages
Sample size: planned number of observations
8,400 women smallholder farmers
Sample size (or number of clusters) by treatment arms
In all treatment arms and the control group, 40 households per village are sampled from the pool of eligible household to make a total sample of 8,400 households.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials