Learning and collaborating towards improved living standards: A field experiment with Nigerian smallholder vegetable farmers

Last registered on June 24, 2024


Trial Information

General Information

Learning and collaborating towards improved living standards: A field experiment with Nigerian smallholder vegetable farmers
Initial registration date
June 04, 2024

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
June 24, 2024, 12:11 PM EDT

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



Primary Investigator

Wageningen University and Research

Other Primary Investigator(s)

PI Affiliation
Wageningen University & Research
PI Affiliation
Wageningen University & Research
PI Affiliation
Wageningen University & Research

Additional Trial Information

On going
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
The vegetable sector is crucial to many smallholder farming households in Kaduna and Kano state in Nigeria, but poor agronomic practices and unfavorable environmental conditions hinder its development. This leaves many households struggling with food insecurity, nutrient deficiency, and poverty. Quality seed of improved vegetable varieties and good agronomic practices have been empirically proven to boost farm productivity and to strengthen livelihoods. Moreover, agricultural extension services play a vital role in disseminating agricultural innovations to smallholder farmers. However, limited access to extension services, coupled with the high cost and last-mile distribution challenges hampers diffusion of knowledge and technology adoption. Research regarding Northern Nigeria has also shown that the access of female smallholders to extension services is more limited in comparison to male farmers, and that they have little agency in decisions that affect their well-being in comparison to their spouse. This research project deploys a randomized control trial to investigate the impact of agricultural extension services and education on intrahousehold collaboration on smallholder vegetable production. It is expected that agricultural extension services will raise farm productivity and education will promote joint decision-making by spouses leading to improved livelihood outcomes for the family.
External Link(s)

Registration Citation

Aju, Stellamaris et al. 2024. "Learning and collaborating towards improved living standards: A field experiment with Nigerian smallholder vegetable farmers." AEA RCT Registry. June 24. https://doi.org/10.1257/rct.13489-1.0
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Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
1. Technology adoption:
- Vegetable production
- Adoption of improved vegetable varieties
- Adoption of good agricultural practices
- Vegetable productivity

2. Livelihood outcomes:
- Home garden production
- Nutrition security
- Crop income

3. Intrahousehold collaboration:
- Project-level Women Empowerment in Agriculture Index (Pro-WEAI)
Primary Outcomes (explanation)
1. Technology adoption:
- Vegetable production: a) Share of farmers that cultivated vegetables, b) Total revenue from vegetables cultivated.
- Adoption of improved vegetable varieties: a) Share of farmers that bought improved vegetable seeds, b) Share of farmers that bought government-certified vegetable seeds, c) Share of vegetable crops of improved variety.
- Adoption of good agricultural practices: a) Share of farmers that adopted at least 5 GAP, b) Number of GAP adopted.
- Vegetable productivity: a) Total value of production for each of the three most commonly grown vegetables (NGN), b) Total value of vegetable production (NGN).

2. Livelihood outcomes:
- Home garden production: a) Total value of vegetable production from the home garden (NGN).
- Nutrition security: a) Household Food Insecurity Access Prevalence (HFIAP), b) Household Food Consumption Score (FCS).
- Crop income Total crop income (value of production of all crops cultivated minus costs of purchased inputs (NGN)).

3. Intrahousehold collaboration:
- Pro-WEAI: a) Self-efficacy, b) Autonomy in income use, c) Input in productive decision making, d) Control over the use of income.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The research studies smallholder farmers in northern Nigeria who cultivate vegetables for local and national markets. The East-West Seed Knowledge Transfer (EWS-KT) foundation assists smallholder vegetable farmers through the provision of agricultural extension services (AES) with the aim of improved farm productivity. EWS-KT works through a train-the-trainer model and first identifies key farmers in target communities.

The EWS-KT model distinguishes between three types of farmers: key, core, and peer/neighboring farmers. Key farmers are selected for being ‘high potential’ farmers who are very influential in their communities, but also based on practical aspects like access to irrigation, and proximity to the tarmac road. Key farmers cultivate an irrigated, centrally located plot and have an entrepreneurial mindset (among other characteristics). A demonstration plot is established on the key farmer’s premises where EWS-KT will train both the key farmer and other motivated ‘core’ farmers from the community. Key farmers manage demonstration plots during the training period. During the season, each key farmer, together with a group of 10-20 core farmers from the same community receives direct training from EWS-KT technical field officers at their demonstration plot. Neighboring or ‘untrained’ farmers receive no direct training but may get exposed through the various facets of the intervention (e.g., presence of a demonstration lot in the village, open training events) or through exchanges with other farmers. Afterwards, farmers are graduated publicly, making them recognizable to others.

This research focuses on three interventions:
• AES training: EWS-KT provides extension training on vegetable production to selected key and core farmers, with separate groups for men and women. Importantly, the same training content is provided to both groups.
• Branding: A training certificate is introduced for successfully trained farmers, awarded in a public ceremony in which the ability of these farmers to share their knowledge within the community is explicitly announced. The hypothesis is that this signal will result in more active interactions and learning from certified farmers. Moreover, these farmers might also benefit from certification through improved market access resulting in better livelihood outcomes.
• Gender sensitization training: This intervention includes spouse training on vegetable production and sensitization messages and discussions about the relevance of intrahousehold collaboration and working together as a family. An extra training session will be included for women-only group on the preparation of bio-pesticides, to increase women’s participation and generate additional income.

This research employs a randomized control trial in 150 communities from eight local government areas in Kano and Kaduna states in northern Nigeria. Treatment is assigned at the community level to account for spillover effects within communities, while data will be collected at the household level. Communities were randomly assigned to one of two main treatment groups or the control group:
• Treatment group 1 (T1): AES training
• Treatment group 2 (T2): AES training and branding
• Control group (C): No AES training and no branding

Orthogonal to the initial randomization, we randomly formed two other groups from the pool of treatment communities only:
• Sub-group 1 (S1): Spouse training and intrahousehold collaboration sensitization
• Sub-group 2 (S2): No spouse training
Experimental Design Details
Not available
Randomization Method
Randomization Unit
This is a cluster-randomized design. The randomization is at the community level.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
150 communities.
Sample size: planned number of observations
In total, 2,562 individuals and one of their spouse (for married farmers) are targeted.
Sample size (or number of clusters) by treatment arms
102 treated communities (T1=52, T2=50; orthogonal from the treatment arm: S1=51, S2=51) and 48 control communities.

In each of the 150 community, farmers are selected in the following way:
• 9 core farmers in each of the 102 treatment communities
• 9 Neighbouring farmers in each of the 102 treatment communities
• 12 Neighbouring farmers in each of the 48 control communities
• 150 key farmers; 1 per community
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Using Stata software, power calculations were computed to obtain the minimum detectable effect sizes (MDES) for the study outcomes. The calculation is based on the priors of the baseline data collection from 3,476 observations. In brief, the study is well-powered and can detect small effect sizes for most outcome indicators (MDES range between 0.001 - 0.116), with perhaps an exception of revenues and incomes. Whereas MDES is less than 30% of the standard deviation for each indicator, it is high compared to the mean. For total vegetable revenue, we can only detect a 30% increase, for total crop income this is even 61%.

Institutional Review Boards (IRBs)

IRB Name
WUR Research Ethics Committee for review of non-medical studies with human subjects (WUR-REC)
IRB Approval Date
IRB Approval Number
IRB Name
International Food Policy Research Institute
IRB Approval Date
IRB Approval Number
Analysis Plan

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