Geographic Distribution of Trained Farmers and the Diffusion of New Agricultural Technology: A Cluster-Randomized Controlled Trial in Madagascar

Last registered on January 06, 2026

Pre-Trial

General Information

Title

RCT ID

AEARCTR-0017558

Initial registration date

December 27, 2025

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 06, 2026, 7:05 AM EST

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

Locations

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Primary Investigator

Name

Ryosuke Ozaki

Affiliation

Japan International Research Center for Agricultural Sciences

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Other Primary Investigator(s)

PI Name

Yuko Nakano

PI Affiliation

Faculty of Humanities and Social Sciences, Tsukuba University

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Additional Trial Information

Status

On going

Start date

2025-09-11

End date

2028-07-31

Keywords

Agriculture

Additional Keywords

Agriculture, Farmer-to-Farmer extension, Agricultural technology adoption, Sub-Saharan Africa

JEL code(s)

O12, O13, Q12, Q16, Q18

Secondary IDs

Prior work

This trial does not extend or rely on any prior RCTs.

Abstract

Agricultural development is essential for food security and poverty reduction in Sub-Saharan Africa (SSA). To investigate how to accelerate the diffusion of new agricultural technologies, this study examines whether geographical distribution patterns of training participants for a new agricultural technology within a commune affects the effectiveness of farmer-to-farmer extension (F2FE). We conduct a cluster-randomized controlled trial, covering 42 communes in the Vakinankaratra region, Madagascar. The intervention provides training on P-dipping, a new fertilization technique for lowland rice, with treatment arms varying the spatial distribution of trainees. This trial includes approximately 3,700 training participants and 1,680 non-trained farmers. The primary outcome variable is the adoption of P-dipping among trainees and non-trained farmers. We further explore the information flow among farmers to investigate the mechanism for the impact.

External Link(s)

Registration Citation

Citation

Nakano, Yuko and Ryosuke Ozaki. 2026. "Geographic Distribution of Trained Farmers and the Diffusion of New Agricultural Technology: A Cluster-Randomized Controlled Trial in Madagascar." AEA RCT Registry. January 06. https://doi.org/10.1257/rct.17558-1.0

Sponsors & Partners

Experimental Details

Interventions

Intervention(s)

Selected farmers receive training on P-dipping, a fertilization technique for lowland rice cultivation. The intervention includes multiple treatment arms that vary the geographical distribution of trained farmers within communes. In each commune, a fertilizer retailer identified prior to the training is invited to participate alongside farmers.

Intervention Start Date

2025-09-18

Intervention End Date

2025-12-31

Primary Outcomes

Primary Outcomes (end points)

Adoption of P-dipping by trainees
Adoption of P-dipping by non-trained farmers

Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)

Information flow among farmers

Secondary Outcomes (explanation)

The information flow among farmers is captured by a dummy variable that takes one if a non-trained farmer i hear about P-dipping from a trained farmer j by time t.

Experimental Design

This study implements a cluster-randomized controlled trial in the Vakinankaratra region of Madagascar, with the commune as the unit of randomization. Among 76 communes where a P-dipping dissemination project run by Japan International Cooperation Agency provides training, we focus on 42 communes in which P-dipping promotion has never been implemented. The 42 communes are randomly assigned to one of three treatment arms, which differ in the geographical distribution of trainees within the commune.
In each commune, the study covers four villages, including the central village with relatively good road access and three additional villages randomly selected from the remaining villages in the commune. In addition to trainees, 10 non-trained farmers are surveyed in village to measure adoption outcomes.

Experimental Design Details

Not available

Randomization Method

Randomization done in office by a computer.

Randomization Unit

Communes

Was the treatment clustered?

Yes

Experiment Characteristics

Sample size: planned number of clusters

42 communes

Sample size: planned number of observations

5,380 farmers

Sample size (or number of clusters) by treatment arms

14 control communes, 14 communes of treatment 1, and 14 communes of treatment 2.

Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Supporting Documents and Materials

IRB

Institutional Review Boards (IRBs)

IRB Name

Comité Malgache d’Éthique pour les Sciences et les Technologies (CMEST)

IRB Approval Date

2025-12-09

IRB Approval Number

195-2025/AM/CMEST-P/

IRB Name

Japan International Research Center for Agricultural Sciences

IRB Approval Date

2025-09-24

IRB Approval Number

JC’ 25/09/26

Analysis Plan