Diffusion Through Dealers

Last registered on March 12, 2026

Pre-Trial

Trial Information

General Information

Title
Diffusion Through Dealers
RCT ID
AEARCTR-0018047
Initial registration date
March 11, 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
March 12, 2026, 4:51 AM EDT

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

Locations

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Primary Investigator

Affiliation
Tufts University

Other Primary Investigator(s)

PI Affiliation
Tufts University
PI Affiliation
Precision Development
PI Affiliation
Golub Capital Social Impact Lab

Additional Trial Information

Status
On going
Start date
2025-09-01
End date
2026-12-31
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Smallholder farmers in Gujarat, India face significant crop losses due to climate-related risks, yet adoption of stress-tolerant seed varieties remains low. This study evaluates a low-cost, scalable intervention that works through agro-dealer networks to improve farmer access to improved seed varieties. Using a randomized controlled trial, we examine both direct effects on dealers who receive the intervention and indirect spillover effects on nearby untreated dealers, with the goal of understanding how climate-resilient agricultural technologies can be diffused cost-effectively through private input supply chains.
External Link(s)

Registration Citation

Citation
Agarwal, Vaishnavi et al. 2026. "Diffusion Through Dealers." AEA RCT Registry. March 12. https://doi.org/10.1257/rct.18047-1.0
Experimental Details

Interventions

Intervention(s)
This study evaluates a randomized intervention promoting a wilt-tolerant chickpea variety through agro-dealer networks across chickpea-growing districts in Gujarat, India, implemented in partnership with a local seed distributor. Distributor-affiliated dealers in treatment markets receive free trial seed packets of the target variety for personal experimentation, along with informational posters and additional packets intended for redistribution to nearby non-affiliated dealers. Non-affiliated dealers randomly assigned to treatment collect their trial packets directly from the affiliated dealer in their market, deliberately creating a new dealer-to-dealer commercial link. All treated dealers additionally receive reminder WhatsApp messages detailing the variety's benefits and procurement options.
Intervention Start Date
2025-10-01
Intervention End Date
2025-11-30

Primary Outcomes

Primary Outcomes (end points)
Dealer stocking of the target wilt-tolerant variety; dealer knowledge of the target variety; dealer recommendations to customers; dealer business size and reach; supplier and dealer relationships; dealer experimentation with the target variety; stocking of other chickpea varieties
Primary Outcomes (explanation)
Primary outcomes are constructed as aggregated indices, each combining a set of related outcome variables collected through dealer surveys and administrative data records. To construct each index, we fix the sign of each component variable based on its hypothesized direction of effect, standardize each variable, and weight components by their variance. This approach reduces concerns about multiple hypothesis testing while preserving sensitivity to theoretically motivated effects.

The primary indices and their components are:
Knowledge about the target variety — includes whether the dealer knows about the variety, knowledge of its attributes, and unprompted identification of the variety as wilt-tolerant and input-efficient from a list of options.
Experimentation with the target variety — includes whether the dealer received a trial seed packet, whether they personally trialed the seeds, whether they distributed seeds to a trusted farmer for trialing, and whether seeds are currently being grown by any recipient.
Stocking of the target variety — includes whether the dealer stocks the variety, quantity stocked, and revenue generated from it.
Advice given to customers — includes whether the dealer actively recommends the target variety to customers, measured through both direct survey questions and an independent secret shopper survey.
Advice given to customers — includes whether the dealer actively recommends the target variety to customers, measured through both direct survey questions and an independent secret shopper survey.
Business size and reach — includes total sales revenue, share of customers who are first-time buyers, and whether the dealer stocked any new inputs.
Relationships with suppliers and other dealers — includes whether the dealer knows the distributor-affiliated dealer in their market, number of new wholesaler relationships formed, number of previous wholesaler relationships discontinued, whether the dealer purchased inputs from the affiliated dealer during Rabi, quantities of the target variety and other seeds sourced through the affiliated dealer and through other sources.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
This study is a randomized controlled trial implemented across markets in chickpea-growing districts of Gujarat, India. Markets are the primary unit of randomization, assigned to treatment or control. Within treatment markets, non-affiliated dealers are further randomized into treatment and spillover control groups, enabling identification of both direct treatment effects and within-market competitive spillovers.
Experimental Design Details
Not available
Randomization Method
Randomization was done using a computer-generated random assignment procedure.
Randomization Unit
Market (for treatment vs. control assignment); individual dealer within treatment markets (for treatment vs. spillover control assignment)
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
51 markets
Sample size: planned number of observations
701 agro-dealers
Sample size (or number of clusters) by treatment arms
Treatment markets: 25 markets, 355 dealers — of which 29 are distributor-affiliated (all treated) and 326 are non-affiliated (approximately half treated, half spillover control).
Control markets: 26 markets, 346 dealers — of which 34 are distributor-affiliated and 312 are non-affiliated (all untreated).
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
For the primary outcome of stocking the target variety, the study is powered to detect an increase of approximately 13.5 percentage points relative to a baseline stocking rate of approximately 3%, assuming an intra-cluster correlation of 0.3, 80% power, and a one-sided test at the 5% significance level.
IRB

Institutional Review Boards (IRBs)

IRB Name
HML IRB
IRB Approval Date
2024-09-30
IRB Approval Number
#2697
Analysis Plan

Analysis Plan Documents

Pre_Analysis_Plan_Scaling_Agrodealer_Distribution.pdf

MD5: 0c44f8e97842cca9168d84b122bdc9bc

SHA1: 12e855a09abecf6f72f5a0f25336185286ad49c8

Uploaded At: March 05, 2026