Evaluating the impact of discount vouchers on the adoption of disease-free shrimp larvae in Bangladesh

Last registered on June 14, 2024

Pre-Trial

Trial Information

General Information

Title
Evaluating the impact of discount vouchers on the adoption of disease-free shrimp larvae in Bangladesh
RCT ID
AEARCTR-0013688
Initial registration date
May 29, 2024

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 30, 2024, 5:47 AM EDT

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

Last updated
June 14, 2024, 4:29 AM EDT

Last updated is the most recent time when changes to the trial's registration were published.

Locations

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Primary Investigator

Affiliation
Michigan State University

Other Primary Investigator(s)

PI Affiliation
International Food Policy Research Institute (IFPRI)
PI Affiliation
International Food Policy Research Institute (IFPRI)
PI Affiliation
Michigan State University
PI Affiliation
International Food Policy Research Institute (IFPRI)

Additional Trial Information

Status
In development
Start date
2024-05-07
End date
2024-12-31
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Ensuring a disease-free environment is a key challenge in shrimp farming, which has consequences on the levels of shrimp production. For an export-oriented product like Bagda, this may subsequently have an impact on the levels of exports. In this study, we study whether different levels of monetary incentive in the form of a discount voucher can reshape farmers' behavior regarding the adoption of a disease-free (Specific Pathogen Free--SPF PL) shrimp post-larvae (PL). We also test whether it can influence the experience of shrimp mortality and disease-related monetary losses, overall mortality rate, total shrimp harvest, and farmers' food security situation. In a randomized controlled trial (RCT), we will distribute discount vouchers among shrimp farmers in southern Bangladesh. We use an open lottery for each farmer to be included in each treatment group.

First, we define the SPF-PL that is available at BDT 800 as type-A, and the SPF-PL that is available at BDT 1200 as type-B. We introduce treatment for both types of SPF-PL.

For type-A SPF-PL, we plan to distribute vouchers worth BDT 100 in treatment arm 1; and vouchers worth of BDT 50 in treatment arm 2. For type-B SPF-PL, we plan to distribute vouchers worth BDT 500 in treatment arm 3, BDT 400 in treatment arm 4, and BDT 200 in treatment arm 5. The rest of the farmers will be assigned to the control group. All the farmers will be provided with the same level of information on the technology and its source. The randomization is done at the individual level using a lottery for each individual farmer. The study will generate research and policy evidence on subsidy and technology adoption in agriculture and aquaculture space.
External Link(s)

Registration Citation

Citation
Bin Khaled, Muhammad Nahian et al. 2024. "Evaluating the impact of discount vouchers on the adoption of disease-free shrimp larvae in Bangladesh." AEA RCT Registry. June 14. https://doi.org/10.1257/rct.13688-2.0
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Experimental Details

Interventions

Intervention(s)
We will introduce discount vouchers for the shrimp farmers as the intervention. These vouchers will be distributed among randomly selected subsets of shrimp farmers so that they can purchase the specific pathogen-free (SPF) post-larvae (PL) to produce shrimp.

First, we define the SPF-PL that is available at BDT 800 per thousand as type-A, and the SPF-PL that is available at BDT 1200 per thousand as type-B. We introduce treatments for both types of SPF-PL. The intention is to make both types of SPF-PL available at least at the level of the price of "normal" (non-SPF) hatchery PL.

For type-A SPF-PL, we plan to distribute vouchers worth BDT 100 in treatment arm 1; and vouchers worth of BDT 50 in treatment arm 2. For type-B SPF-PL, we plan to distribute vouchers worth BDT 500 in treatment arm 3, BDT 400 in treatment arm 4, and BDT 200 in treatment arm 5. The rest of the farmers will be assigned to the control group. All the farmers will be provided with the same level of information on the technology and its source. The randomization is done at the individual level using a lottery for each individual farmer. Each individual farmer will be eligible to buy up to 16 thousand SPF-PL. The highest amount to be purchased is determined based on the recommended level of SPF-PL release on a 100-decimal pond.
Intervention Start Date
2024-06-19
Intervention End Date
2024-09-30

Primary Outcomes

Primary Outcomes (end points)
We consider the following as the primary outcomes:
(1) Intention to treat (TT) analyses:

(i) Purchasing SPF-PL (1/0): We define the purchase of SPF-PL as binary for each individual (1/0), in the stocking period after the distribution of the vouchers
(ii) Quantity of the SPF-PL purchased: We use the total amount of purchased SPF-PL in the stocking period after the distribution of the vouchers.
(iii) Plan to purchase the disease-free PL in the next production cycle: We define the binary outcome variable as 1 when the farmer plans to purchase the SPF-PL in the next production cycle.

(2) Local Average Treatment Effect (LATE) analyses:

(i) Mortality: We define mortality as binary if an individual farmer experiences any mortality in the stocking period after the distribution of the voucher.
(ii) Percentage of mortality: We define this as the percentage of overall mortality in the pond in the stocking period after the distribution of the voucher.
(iii) Monetary loss: We measure the approximate losses in BDT in the stocking period after the distribution of the voucher.
(iv) Gross value of shrimp output produced: We measure the gross value of the shrimp output in terms of BDT in the stocking period after the distribution of the voucher.
(v) Weight of harvested shrimp: We define it in terms of the kilogram quantity of shrimps harvested in the stocking period after the distribution of the voucher.

(vi) Food Insecurity Experience Scale (FIES) score: We will use the FIES score generated using the widely used Household Food Insecurity and Access Score (HFIAS)
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The study will evaluate the impact of discount vouchers at different levels in the context of shrimp farming in the Southern region of Bangladesh. The International Food Policy Research Institute (IFPRI), Michigan State University, WorldFish, and Alliance Bioversity-CIAT are collaborating on this experiment. This study will use a sample of shrimp farmers to conduct a randomized controlled trial (RCT).

There is an existing sample of 1222 shrimp farmers in the southern region of Bangladesh from a study conducted by the International Food Policy Research Institute (IFPRI). IFPRI is conducting a second round of surveys from May 2024 to collect information on demographic characteristics, production, and farming practices. This survey is taking place in the comfort of the subject's home or farm. After this survey, discount vouchers will be distributed among randomly selected subsets of shrimp farmers so that they can purchase the specific pathogen-free (SPF) post-larvae (PL) to produce shrimp.

For type-A SPF-PL, we plan to distribute vouchers worth BDT 100 in treatment arm 1; and vouchers worth of BDT 50 in treatment arm 2. For type-B SPF-PL, we plan to distribute vouchers worth BDT 500 in treatment arm 3, BDT 400 in treatment arm 4, and BDT 200 in treatment arm 5. The rest of the farmers will be assigned to the control group. All the farmers will be provided with the same level of information on the technology and its source. The randomization is done at the individual level using a lottery for each individual farmer. The enumerators will conduct the lottery in front of the farmer to ensure transparency. Each individual farmer will be eligible to buy up to 16 thousand SPF-PL. The highest amount to be purchased is determined based on the recommended level of SPF-PL release on a 100-decimal pond.
Experimental Design Details
Not available
Randomization Method
Individual level lottery during visits
Randomization Unit
Randomization is done at the level of individual farmers.

Note that priorly, three specific group of interventions were introduced among the shrimp farmers in the Southern region of Bangladesh. These interventions can broadly fall under different cluster participation programs which are being implemented by: (1) the Department of Fisheries, Government of Bangladesh (under the World Bank-funded Sustainable Coastal and Marine Fisheries Project [SCMFP]), henceforth DoF; (2) ACI Agrolink Ltd., henceforth ACI; and (3) the Bangladesh Shrimp and Fish Foundation (BSFF). These three represent diverse actors, including government, private sector processor cum input firm, and industry advocacy body.

In our current study, a cluster of farmers is a group of farmers defined in the following manner. In each cluster, we have three types of
randomly selected shrimp farmers:
(i) farmers who have formed a group based on either DoF-prescribed guidelines or ACI/BSFF-prescribed guidelines where they farm in contiguous ponds. We can say that these farmers participate in one of the cluster participation programs introduced by the entities mentioned above.
(ii) farmers of the same village who do not participate in the cluster participation programs,
(iii) farmers who farm in an adjacent village and do not participate in the cluster participation programs.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
Clustered at the individual level
Sample size: planned number of observations
1222 shrimp farmers
Sample size (or number of clusters) by treatment arms
Based on the lottery at the individual level conducted by the enumerators during the visit, we expect to have approximately 200 shrimp farmers in each treatment arm.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB

Institutional Review Boards (IRBs)

IRB Name
Michigan State University IRB
IRB Approval Date
2024-04-16
IRB Approval Number
MSU Study ID: STUDY00010661