Measuring Spillover Impact of a Market Access Program of Avocados in Kenya

Last registered on July 19, 2023


Trial Information

General Information

Measuring Spillover Impact of a Market Access Program of Avocados in Kenya
Initial registration date
July 07, 2023

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
July 19, 2023, 12:07 PM EDT

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


Primary Investigator

Swedish University of Agricultural Sciences

Other Primary Investigator(s)

PI Affiliation
Pennsylvania State University
PI Affiliation
Pennsylvania State University

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
This project studies the economic impact of a certification program to avocado farmers in the Mount Kenya region. A large non-profit organization in the area allows farmers to get their Hass avocado crops certified ahead of the avocado season. Upon receiving certification, farmers enter into an agreement with the NGO, which ensures that the NGO will purchase their avocados at a higher price. The NGO then exports these Hass avocados to Europe. We partnered with this NGO to estimate the direct and indicret impact of this certification program. We are interested in estimating the differences in prices, revenue and profits between (i) farmers with and without certification, and (ii) uncertified farmers in areas with certification compared to those in areas without certification. We propose that the certification program could be boosting the earnings of all avocado growers in the Mount Kenya region - not solely those with certification. Our identification strategy relies on the fact that the latest expansion of the certification program was carried out randomly at the subcounty level.

External Link(s)

Registration Citation

Mensah, Edouard , Pedro Naso and Mare Sarr. 2023. "Measuring Spillover Impact of a Market Access Program of Avocados in Kenya." AEA RCT Registry. July 19.
Sponsors & Partners

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

Request Information
Experimental Details


A prominent NGO in the Mount Kenya region provides a certification program to farmers growing Hass avocados. If a farmer gets certified, which requires some basic modifications in farm organization and hygiene practices, they can sell their Hass avocado yield to the NGO at a higher price. This certification initiative began in 2022 in 9 sub-counties around Mount Kenya, and the NGO is gradually broadening the locations offering certification. The most recent expansion of the program was conducted randomly at the sub-county level, which allows us to determine the causal impact of the certification program. We evaluate two types of effects, direct and indirect, by comparing:
(i) Certified and non-certified farmers (Direct Impact);
(ii) Non-certified farmers in areas with and without certification (Indirect Impact).
Our research focuses on three variables: the price farmers charge for avocados, avocado revenue, and avocado profits. We propose that the certification program may increase avocado prices in the region, both in sub-counties where certification is available and in those where it is not. Furthermore, we believe that all avocado varieties (Hass, Fuerte and local varieties) in the region might see a price rise.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Avocado prices, avocado revenue (prices times quantity), and avocado profits (revenue minus costs of production). We will estimate these outcome variables for all farmers we survey and for all varieties of avocado (Hass, Fuerte and local varieties).
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
We are also interested in brokers activity in the region. So, we will also work with the variables: prices offered by brokers, frequency of brokers visit, and number of different brokers.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
In partnership with a large NGO that operates in the Mount Kenya region, we randomize the expansion of a certification program for Hass avocado farmers at the sub-county level. In treated sub-counties, farmers growing Hass avocados can join the certification program, which calls for some elementary changes in farm organization and cleanliness measures. After obtaining certification, these farmers can sell their Hass avocados to the NGO at a price above the regular market rate. We compare these treated farmers with three types of farmers:
(i) Uncertified farmers based in sub-counties where there is certification (control group 1). These are also non-elegible for certification;
(ii) Uncertified farmers who are elegible for certification but are based in sub-counties where the NGO does not offer certification (control group 2);
(iii) Uncertified farmers who are not elegible for certification and are based in sub-counties where the NGO does not offer certification (control group 3).
We then estimate direct impact comparing certified farmers with control group 2; and spillover impact comparing control groups 1 and 3. We focus on three variables of interest: average avocado prices, avocado revenue, and avocado profit. These are measured for the most important varieties of avocado in the region: Hass, Fuerte and local varieties.

Experimental Design Details
Randomization Method
Randomization was done in office by a computer.
Randomization Unit
Cluster: sub-counties in the Mount Kenya Region
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
We will have 32 clusters: 16 treated (where there is the possibility of certification) and 16 control (where there is no possibility of certification).
Sample size: planned number of observations
45 farmers per cluster, which is equivalent to 1,440
Sample size (or number of clusters) by treatment arms
16 treatment clusters and 16 control clusters
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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

Request Information


Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials