Expanding Market Access to the Last Mile of the Fertilizer Value Chain: Complementarities between OCP Farmer Houses and Village Input Fairs in Senegal

Last registered on May 11, 2026
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Pre-Trial

Trial Information

General Information

Title
Expanding Market Access to the Last Mile of the Fertilizer Value Chain: Complementarities between OCP Farmer Houses and Village Input Fairs in Senegal
RCT ID
AEARCTR-0018559
Initial registration date
May 05, 2026

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
May 11, 2026, 8:47 AM EDT

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

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Primary Investigator

Name
Andrew Dillon
Affiliation
Northwestern University
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Other Primary Investigator(s)

PI Name
Nicolo Tomaselli
PI Affiliation
Northwestern University
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PI Name
Fatou Fall
PI Affiliation
RWI- Institute for Economic Research
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Additional Trial Information

Status
In development
Start date
2026-09-01
End date
2028-05-31
Keywords
Agriculture, Behavior
Additional Keywords
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Last mile problems are a feature of rural economies where the poorest farmers often have the least access to extension advice and access to markets. We propose to test the effect of two last mile solutions and their integration. The OCP Farmer House extends the fertilizer value chain to rural secondary towns which serves as a hub for agricultural inputs, extension advice, and agricultural services. The Village Input Fair model (Dillon and Tomaselli 2024) creates rural input markets in villages by organizing ag-dealers in the post-harvest period to facilitate input purchase orders. Independently, extension or market access may increase farmer input demand, knowledge, yields and welfare. Bundled, the OCP Farmer House and Village Input Fairs may further increase the key outcomes by integrating the input supply chain improving market access to rural smallholder farmers. Our proposed design will allow us to disentangle the effects of each invention independently and together while estimating heterogeneous treatment effects by distance to secondary towns where Farmer Houses are based. Integrated with the quantitative impact evaluation will be a lab-in-the-field experiment and a qualitative exploration of farmer trust, a key constraint to the introduction of new market institutions required to implement last mile innovations in rural contexts.
External Link(s)

Registration Citation

Citation
Dillon, Andrew, Fatou Fall and Nicolo Tomaselli. 2026. "Expanding Market Access to the Last Mile of the Fertilizer Value Chain: Complementarities between OCP Farmer Houses and Village Input Fairs in Senegal." AEA RCT Registry. May 11. https://doi.org/10.1257/rct.18559-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2026-12-01
Intervention End Date
2027-12-31

Primary Outcomes

Primary Outcomes (end points)
This RCT aims to answer the following research questions:
● What is the change in farmers’ input demand and second-order effect on farm productivity and farmer welfare when:
○ Input supply chains and agricultural advice are extended to secondary towns through Farmer House interventions?
○ Input supply chains are extended to villages through village input fairs?
○ Input supply chains and agricultural advice are extended at both the secondary town and village levels through Farmer Houses and village input fairs?
● How does geo-spatial variation in a village’s distance to secondary towns affect take-up, input
demand, and farmer productivity across the three treatment groups?
● What role does trust play in influencing farmers’s willingness to participate in and commit to village input fairs?
● How does trust in agro-dealers or agri-promoter (Farmer House) agents influence farmer participation in VIFs or take-up of inputs?
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The evaluation is a clustered randomized control trial designed to see the effects of both interventions on adoption of fertilizer. Our impact evaluation will have three treatment arms and one control group with no intervention for comparison:
● Treatment arm 1: Farmer House Marketing Encouragement
● Treatment arm 2: Village Input Fair
● Treatment arm 3: Both Farmer House Marketing Encouragement and VIF
● Control group: No Marketing or VIF in the village
The unit of randomization is at a village level. Both interventions are organized at the village level and are aimed at targeting the entire village.
Experimental Design Details
Not available
Randomization Method
Randomization done in office on a computer
Randomization Unit
Treatment is randomized at the village level.
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
180 villages
Sample size: planned number of observations
10 household per village, 1800 households
Sample size (or number of clusters) by treatment arms
● Treatment arm 1: Farmer House Marketing Encouragement - 45 villages
● Treatment arm 2: Village Input Fair - 45 villages
● Treatment arm 3: Both Farmer House Marketing Encouragement and VIF - 45 villages
● Control group: No Marketing or VIF in the village - 45 villages
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number
Analysis Plan