Information Diffusion in Agricultural Social Networks under Externalities: A Pest in Honduras
Last registered on February 11, 2019


Trial Information
General Information
Information Diffusion in Agricultural Social Networks under Externalities: A Pest in Honduras
Initial registration date
February 06, 2019
Last updated
February 11, 2019 4:00 PM EST

This section is unavailable to the public. Use the button below to request access to this information.

Request Information
Primary Investigator
International Food Policy Research Institute
Other Primary Investigator(s)
PI Affiliation
PI Affiliation
Additional Trial Information
On going
Start date
End date
Secondary IDs
We use agriculture social network data from over 100 communities in Honduras and identify farmers to target and train on new technology and practices to prevent and control a new pest that posits negative externalities to the community. A randomized controlled trial compares targeting approaches in their effectiveness for information diffusion within existing networks. The targeting strategies rely on: community leaders of existing institutions, theory-driven network statistics, community nominated to best transmit a message, and random farmers within the network. The comparison provides information on the cost-effectiveness and scalability of these targeting strategies
External Link(s)
Registration Citation
ALMANZAR, MIGUEL, Cristina Chiarella and Maximo Torero. 2019. "Information Diffusion in Agricultural Social Networks under Externalities: A Pest in Honduras." AEA RCT Registry. February 11.
Sponsors & Partners

There are documents in this trial unavailable to the public. Use the button below to request access to this information.

Request Information
Experimental Details
An individual/personal training session with selected farmers in communities affected y the yellow aphid in Honduras. These trainings are aimed to transmit three key messages or lessons: i) how to identify and monitor the yellow aphid in sorghum and maize, ii) how to control the yellow aphid once it has affected the crop, and iii) how do pest spatial externalities affect the community, not just the individual, and how can they be prevented through cooperation.
Solutions will be shared with the participants through multimedia and interactive learning activities that are adapted to the local context. We will also provide each participant with the tools to implement these solutions: a calendar that contains the key messages from the training and serves as a tool to keep their scouting records, and yellow traps. In addition, each training participant receives a set of calendars and yellow traps for identified members in their community, to which we ask them to deliver them to and communicate the lessons learned during the training.
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
Identification and Knowledge: Correctly identifies yellow aphid from different images, Names unique characteristics of yellow aphid

Use of Solutions: Monitoring, alertness and diligence: Reports performing regular scouting for yellow aphid, Keeps a yellow aphid scouting, record on their calendar, Estimates number of yellow aphid from images, Correctly identifies number of areas and places were to perform yellow aphid scouting

Use of Resources: Yellow traps and home-made insecticide solution, Identifies yellow traps and detergent solution as effective measures to control yellow aphids, Correctly knows how install yellow traps (spacing and placement), Correctly identifies ingredients and quantities to make sustainable detergent solution to use as insecticide, Installed yellow traps in the previous agricultural season, Applied detergent solution as insecticide if exposed to yellow aphid, Knowledge of management of infected plants and weeds to minimize further contagion

Collective action and externalities: Received information or heard of yellow aphid infestation in the community from neighbors, Provided information of yellow aphid infestation in the community to their neighbors, Received training and calendar tool package from an injection point trained in the experiment, Received training, calendar tool package, or information on yellow aphid from a non-injection point (other trained by an injection point of the experiment), Used calendar tool to record neighbors s/he informed and/or trained in the previous agriculture season

Effectiveness of training in final outcomes: Probability of having had a yellow aphid problem in the past agricultural season, Probability of planting and not harvesting due to yellow aphid, Quantity of sorghum lost on field and quantity harvested, Sorghum productivity or yields, Food security: Probability of being hungry and availability of grains in the household
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
To compare the effectiveness of the different methods on reaching most farmers and achieve coordination, we will test three different injection points based on defined characteristics and positionality in the social networks. These three injection points will be compared with a group of communities where random farmers initially receive the information. In addition, these four treatment conditions will be compared to a control group, where no farmer will receive the training.
The network characteristics that define the injection points are:
a. Local Leaders: social capital and institutions
b. Diffusion central: network theory/statistics
c. Community nominated: the people’s voice
d. Random farmers: natural diffusion
Experimental Design Details
Not available
Randomization Method
Randomization done in office computer on baseline data.
Randomization Unit
Communities (caseríos)
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
221 communities
Sample size: planned number of observations
Sample size (or number of clusters) by treatment arms
a. Local Leaders: social capital and institutions: 28 communities
b. Diffusion central: network theory/statistics: 28 communities
c. Community nominated: the people’s voice: 28 communities
d. Random farmers: natural diffusion: 27 communities
e. Pure control: 110 communities
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
We calculated the minimum detectable effect on a set of outcome variables: whether the farmer has faced infestation of any of the two pests, if farmer is able to identify them, if correctly identifies the pest (from pictures presented), if mentions some measure to control such pest, total crop production and total crop area. We varied the number of clusters per treatment arm and found that using 25 clusters (or communities) per treatment arm will allow us to detect a change of between 4 to 11 percent points in the mentioned binary outcome variables.
IRB Name
The International Food Policy Research Institute Institutional Review Board
IRB Approval Date
IRB Approval Number
Analysis Plan

There are documents in this trial unavailable to the public. Use the button below to request access to this information.

Request Information